# How can Santa defend himself?

The world is full of grinches. Party-poopers who simply insist on taking the fun away from everybody else. They'll do everything they can to stop Santa from delivering his gifts — and too many of them work in militaries across the world.

What's amazing is that Santa is a really nice guy! He doesn't want to hurt anybody, but he has a job to do! And NORAD going out of their way to tell everybody where Santa is every second of the trip doesn't help.

Santa has access to his world-renowned workshop, but all he has in transit is his sled. It has a near infinite carrying capacity — but it is just a sled (with exposed reindeer... Dang...).

Question:  What can Santa do to defend himself from the world militaries of 2018?

• Remember, all you have to work with is the sleigh and eight (OK, nine) reindeer. Santa can't send his elves to invade Somalia to nullify their military — or their pirates.

• Santa won't hurt anyone, so whatever defenses you come up with must preserve human life.

• Santa, the sleigh, and all the reindeer must survive the day.

• Our grinches may want Santa dead, but their children probably don't. That means Santa is required to stop at every military base. He can't save his can by avoiding launch sites, ifyouknowwhatImean.

• If he travels at the speed of light, none of his enemies can see him coming until after he's gone. I don't believe modern military technology is built for a target like that. – workerjoe Dec 24 '18 at 19:25
• Futurama 🎅 Santa – Evorlor Dec 24 '18 at 22:27
• The question specifically states that NORAD is tracking Santa. The entire premise is based on the assumption that people know exactly where he is at any given time and want to do him in. – Ian Johnson Dec 26 '18 at 3:18
• Too late! They got him: gocomics.com/wizardofid/2018/12/27 – nzaman Dec 27 '18 at 15:48
• NORAD, the red herring, IS Santa's defense. Shoot... some people around the world get their gifts on St. Nicholas' Day on December 5th/6th or 18th/19th, while others look to receive on Christmas Dec. 24th/25th or Jan. 6th/7th. Depends on the country and calendar. And never mind the Grinch-countries that don't even celebrate?! For shame... – OhBeWise Dec 27 '18 at 21:08

Shame

Ever wondered why Santa Claus goes "ho ho ho"? Turns out it means exactly what you think it means. Santa keeps an additional naughty list of unfaithful married couples, especially those high in the political ladder and the military chain of command. One wrong move and the whole world gets to find out how much of a ho-ho-ho you or your spouse has been

Alternative "countermeasures"

For would-be grinches lower in prominence, Santa has other methods. Let it not be said that he's a one trick reindeer.

Santa has been utilising psyops long before there was even a NORAD. The commercialisation of Christmas was part of his master plan. All the trappings of Christmas, like gifting, endless jingles, Whamageddon etc, are a sustained DDoS(Distributed Disruption of Surliness) attack waged by the corporations who are really Santa's proxy botnet.

On the big day itself, Santa deploys his air force to clear the way. Using their powerful ECM(Extremely Childlike Merriness) packages, highly trained elf pilots flying dedicated strike festives perform SEAD(Shutting-up Extremely Annoying unDesirables) missions. They are supported by AWACS(Archaic Wassailing And Carolling Sleighs) craft who perform command and control duties over the airspace. These provide guidance and help out with their ECCM(Eggnog-Caused Conclusive Meliorism). NORAD never stood a chance.

• +1 for providing an answer that fits Santa's existing MO. (Blackmail) – ThunderGuppy Dec 26 '18 at 14:40
• Perfect! Your addition tipped the scales. – JBH Dec 27 '18 at 20:35

Santa is the last active user of the SR71 defence mechanism, he's just too fast.

A quick and dirty calculation of how many deliveries he has to make in a single night, and the distance he has to travel to make those deliveries, suggests that he's moving far faster than anyone is able to intercept.

We might be able to track him, NORAD may know exactly where he is, but they've got nothing actually able to hit him.

• @JBH, I haven't done the calculations myself, but I believe at the speeds he's travelling hitting a raindrop could be lethal. He'll have to be pretty good at dodging things in the air. – Separatrix Dec 24 '18 at 17:01
• @JBH: It's not the speed, it's the acceleration. Santa's sleigh accelerates from zero to relativisticly significant fractions of c and back to zero again in the space of two houses. – Joshua Dec 25 '18 at 2:32
• @JBH: At this point I'm busy looking up whether or not a kinetic collision with Santa's sleigh is we just nuked a city or not. – Joshua Dec 25 '18 at 2:37
• I am pretty sure Santa is actually a wave. – Sulthan Dec 26 '18 at 9:47
• @Sulthan, I think that could be expanded into an answer in its own right for several related questions – Separatrix Dec 26 '18 at 9:51

Santa is protected by mutual ensured destruction, the same force which arguably protected us during our nuclear infancy.

It works like this...

Santa is the only reason why children even attempt to stay off the naughty list.

Without that incentive, those little rug rats would be completely uncontrollable.
Destruction doesn't even begin to describe what they would do if anyone took out Saint Nick.

Think about this, as parents, you are the source of every disciplinary scolding and every bottom swat that your children have ever received. ...and they know where you keep the butcher knives.

NORAD doesn't admit it, but they send up a wing of fighter jets to escort and protect the sleigh while it is over US Protected airspace. Most of the other countries do the same, and CIA drones cover those countries which lack the good sense to put up their own defense.

Santa does not have to worry about protection because the rest of us grown-ups worry for him. That is why parents always look so weary on Christmas morning. They have been up all night wishing...

Merry Christmas To All and To Nick A Safe Flight!

• OK! +1 for Santa is the only reason why children even attempt to stay off the naughty list. And all this time I've been worrying about a Zombie apocalypse! – JBH Dec 24 '18 at 17:11
• First of all, fighter jets aren't fast enough to keep up with the speeds Santa must be traveling to deliver all those presents in a single night. Second, how are fighter jets gonna cover Santa once he's come down my chimney? If I'm camping the fireplace with a shotgun, are you telling me that the fighter jets are gonna blow my house up with missiles? And you can't just assume Santa won't come to my house because anyone who wants to kill Santa is on the Naughty List. What if others in my house are on the Nice List? Unless he has wall hacks and just avoids me. – Ian Johnson Dec 26 '18 at 3:25

Counterintelligence and stealth technology.

It is well established that Santa has to travel at the speed of fantasy to be able to deliver all the gifts in time around the world. The only way to catch him is using air force and radar.

First of all his sledge is built with the latest stealth technology, which most of the radar cannot track. But the guys of NORAD have the technology to follow their own stealth planes, so something more is needed.

His chubby appearance is a clever disguise for a secret anti radar technology, well hidden under the red coat, which offsets the radar echo tricking the NORAD into giving a false position.

And just as additional measure, he makes sure to deliver the gifts first to the party-poopers, so that while they are busy unwrapping he can visit the rest of the area.

• +1 just for his chubby appearance is a clever disguise for a secret anti-radar technology. I about choked on my hot chocolate from laughing. – JBH Dec 24 '18 at 16:19

Nobody can actually track him

It's been established that the speed and route that Santa has to take are, to put it lightly, absurd. But that's not any fun, and Santa knows this. To help him keep the christmas spirit in children while also accomplishing his job, Santa employs a significant number of look-alikes, drones, and other equipment.

Some just need to look like a sleigh and reindeer, to let the children catch a glimpse. There's no way they'd be seeing him at an average speed of ridiculous, so these let them enjoy the magic while he does the actual magic.

Some are more complex. Maybe with an additional set of reindeer and an elf in a replica sleigh. Or, more accurately, a replica of what people think the sleigh looks like. The actual sleigh is probably a bit different, given the abuse it has to endure.

And there's even some that aren't meant to be seen by eyes. They give off the correct radar signature, and one of these is famously tracked by NORAD.

Meanwhile, Santa zips around in an undetectable fashion, possibly breaking the laws of physics and/or time. While he knows he is perfectly safe on those counts, he likes the way people think of him, so he takes efforts to make sure he doens't spoil the magic. Plus, if a kid is awake, a well-timed drone outside the window can give him the opportunity to sneak in, eat the cookies, drink the milk, and drop off the presents without being seen.

People have tried to sneak up on Santa. As they have found out, he sees them when they're sleeping, he knows when they're awake.

• Clever. More so for being true. Please elaborate in such a way the particulars of the query are addressed. – elemtilas Dec 26 '18 at 14:43

# Sheer weight of numbers

Sure you can knock out a few Santas, or even a few dozen but it's like pissing on a forest fire. There are millions of them coming over to be able to complete the round in time. Perhaps a few children will miss out, but with the best will in the world, you're not going to be able to put a dent in their numbers.

Hundreds, maybe thousands of Santas may fall to the Grinches in a hard year, but still they come, millions strong. The swarms of Santas flying over turns the sky dark as they pass, a sight to bring joy to the heart of any child1.

1and great fertility to the fields as the reindeer do what reindeer do.

Posted as a separate answer because it's entirely unrelated to my other one

Santa plays by Mutually Assured Destruction rules.

We see the one sleigh he normally uses, but anybody who runs operations like this one has backups capable of completing the entire job just in case something goes down.

Santa has to make not less than 233,000,000 stops, and travels between houses at an average speed of 1,800 miles per second. If we assume a smooth acceleration curve his peak velocity is double, but to make it more fair for the militaries of the world, we won't do that.

Santa's sleigh must therefore possess 838,800,000,000 miles per second of delta V and some stupid huge TWR. If this is provided by fuel at all, it had better be some kind of mass cancelling magical storage because if it's ordinary antimatter I'd be amazed if the calculations don't work out to this being a planet buster (update: the starting fuel as antimatter outweighs the earth). If someone takes him out, it had better be a clean kill, or any remaining reindeer are going to be panicked and ludicrously dangerous to approach.

In any case, the elves with the backup sleighs will have no significant trouble demolishing the military might of the world by shockwaves alone. Somehow, Santa is cancelling his shockwaves from the stupid huge acceleration to keep the cities from being blown away. All the elves have to do is don't.

What NORAD detects is a drone bogey to keep them occupied, while he uses a more discreet method of travel.
And for that matter, the sleigh doesn't have infinite capacity, the sack does.

• You've got a good point about the sack. But it's infinite by weight and volume. The sleigh, therefore, must have infinite weight capacity, but not necesarily volume.... Hmmm... that's almost worth a separate question... Except Santa must be capable of lifting the sack, which suggests weight-nullifying tech. Of course, if he can do it with the sack... I mean, come on, even eight reindeer would struggle against the full weight of the fat man, right? – JBH Dec 24 '18 at 16:57
• @JBH: Hence why the sleigh and deer are for show. They couldn't possibly lift all that. Put 3 elves on top of each other and stuff 'em in a fat suit, then tie them onto the sleigh. The reindeer know the route they're supposed to take to keep the radar people busy – nzaman Dec 24 '18 at 17:02
• @nzaman, oh those poor elves! – No Name Dec 25 '18 at 2:04

Since Santa and the reindeer live at the North Pole for so long, they have evolved ways to not radiate so much body heat, internalizing it as much as possible. This makes it extremely difficult for heat seeking armaments to lock onto them.

For radar... well, that sack probably has a ton of tinsel that can be used as chaff.

And then there's the whole prospect of going down in history as the person that ended gifts for the whole world. Can't say that would make one popular. I highly doubt anyone will buy you a drink at the bar if you're the one that offed Santa.

# Multiple dimensions and time travel

As we know, Santa has to move really fast to get to everyone, so instead he has developed technology that allows him to be in multiple places at once. He can visit 50 or more houses at a time due to his multi-dimension "clones" of himself. They are all the same person, just different time versions. Sort of like time remnants from the TV show "The Flash", or the time doors/gates in the later seasons of "The Legends of Tomorrow".

He moves through time and dimensions/space, instead of his standard flight pattern. We still see it as that standard flight pattern, but that's not how he really moves. (See the next heading/section for why he doesn't have to dodge anything.) Also, since he doesn't want any missile or other fragments to hit innocents, he uses the same tech to capture the ammunition and transport it to a place where it will be made harmless, like deep space.

He never has to refill his bag, since he's always directly coming from his workshop. All of his time "clones" use this same bag, too, since they really are just him. In fact, he spends all of his year delivering packages, it's just that he plans it out so that it appears he is doing it all on a single night. If you manage to follow him back to his shop, it might actually be July at the North Pole, instead of December.

This is how he gets into houses, rather than chimneys that most people don't have anymore. He simply "transports" into the house instead of the roof.

# Holograms

The Santa you might accidentally see in flight or on your neighbors roof is actually just a hologram. The sleigh and reindeer have been in retirement for years from actual flying. They are still used to make lifelike holographic recordings, but they stay warm and safe at the North Pole.

Since he's going to so many houses and many of them leave cookies and milk for him, he uses this as fuel for his equipment. Sure, he still snacks some (you don't stay fat by eating right and getting as much exercise as he does), but there are a lot of calories that can be turned into bio-fuel in cookies, milk, and the other snacks people leave for him.

He is working on using the explosives and other ammo (collected while "flying") for his energy consumption use, but I hear they've hit some snags with containment.

# Clones

Due to the ever increasing population, extremists, and the possibility of future generations being on remote planets, his elves have been working on clones. They are exact duplicates of Santa, including all of his previous memories, like "The 6th Day".

So far, they have only been using a single clone at a time, but things are progressing so that they will need to use multiples soon. Because of this, his elves are also working on memory combination, so that if you meet one Santa one year, they all will have the same memory of meeting you. This is sort of like distributed SQL databases over multiple servers. Just like you might make an order on Amazon in one database on one server, that information is replicated to all other databases on other servers for data retrieval as well as backup use.

Even if he enters a household with an extreme defensive position, his body armor suit (yes, the red one with white fluffy borders) can only defend against so much. If he accidentally dies, his next clone takes over with the latest memories intact. Part of his hat is a memory detector and recovery device, besides being a helmet.

Of course, anytime he meets resistance, that person goes on the permanent "naughty" list. It's not necessarily the person "pulling the trigger" on the list, but the person giving the order gets blacklisted.

# Conclusion

Ok, so I went beyond mere defense here, but I had to explain why he doesn't really need to defend against military attack: he just isn't flying anymore. However, he still makes sure there isn't any collateral damage, using the same time/space transportation tech.

And for close combat assaults, he wears armor. When even that doesn't save him, Santa uses clones to replace himself.

The answer is quite simple. Santa isn't real, so needs no defenses.

It's a vast world-wide conspiracy. Those who are grown-ups now perpetuate the ruse out of nostalgia and whimsy, but they know, deep down, that it's all for show. They are the ones wrapping extra presents for the kids. They are the ones putting the children to sleep with the hope of Santa dropping in. They are the ones eating the cookies. It goes all the way to the top, and has for years.

And yes, this answer is obviously ridiculous, because why would so many people go along with it? I mean, it doesn't make much sense at all, really. But this is Worldbuilding, so I assume that's allowed.

• This is, indeed worldbuilding! And this sounds like the start of a plausible conspiracy to control the spending habits and parental behaviors of adults to me. It just needs a reason and a control mechanism. :-) – JBH Dec 28 '18 at 18:24
• I see what you did here. I'd comment further but I have to go eat some cookies. Edit: Uuuh... I mean wash some laundry and wait for Santa. – The Great Duck Dec 31 '18 at 11:22

Santa already has defenses! While their purpose is simply protection from the environment in which he operates they're plenty strong enough to shrug off anything the military of any nation can throw, up to and including a direct hit with a nuclear weapon. Even the biggest booms are nothing compared to the atmosphere at the speeds he must be moving in order to make his deliveries in a day and a half.

Santa is a cunning man. As a maker of toys he has a natural supply of decoys, including other fake pop-up Santas and reindeer. And although NORAD thinks they have him tracked, it's actually a decoy transponder that he plants on a lookalike sleigh.

Equipped with an arsenal of loud noisy things, insta-pop-up balloon Santas, disco smokescreen machines, loud fireworks, he's the master of misdirection and distraction. After all, how do you think he gets past all those eagle-eyed children who are looking out for him?

Santa has another gift: he can see into people's hearts, and knows what they truly want, that's how he knows they've been naughty or nice. Even the most hardened military soldier is going to melt when they find Santa brought them something precious, like a card from a loved one, photograph or even a puppy. Sargent might not be too happy.

With some kitted out defence tech

But automated systems can't be bought with gifts. What's Santa to do when his sleigh is undoubtedly detected on radar and IR-tracking missiles? Santa has some close friends in the military who've kitted out his sleigh with chaff, both heat-producing and radar baffling (electronic chaff), of which Santa has modified to also launch fireworks and sparklers and other heat producing sources. He's a jolly fellow like that.

He's also managed to get some electronic system scramblers, so when he's closer the radar systems will be jammed.

With favours

Santa is a popular guy. He's helped many out of a bad situation, and some even owe him a few favours. Blackmail is beneath Santa, as a man of integrity, but he knows a few people who owe him some favours (he once got a stretch armstrong for a guy when it was sold out, long story).

Some of them might be able to provide distractions. There's one kid who is really good with tech, can hack computer systems remotely (he need not travel with Santa, internet is a wonderful thing and Santa has built in wifi because what sleigh doesn't?).

Maybe a few people might read between the lines and knock out a few guards. Santa doesn't approve of course, but as it's not Santa it'll pass.

With reindeer

Now, Santa isn't allowed to go around beating up the occasional bad guy, but Blizter, he's got a real bad attitude, he's really grouchy. Well, all the reindeer can be if you get between them and Christmas.

With antlers and their own mind (almost like they know what they're doing) they might opt to... intervene. They are magic reindeer after all.

With a child ambush

Of course, children love Santa and if they see a jerk trying to harm Santa, well, they're about to get jumped by an ambush of children. Shin kicking, direct hits to the groin, eye poking, make up powder in the eyes, enough to make any wrongdoer think twice.

The real meanies

Santa's not really one to hurt anybody. But then there are the real meanies, the people whose hearts can't be melted with puppies, can't be fooled with plastic decoys or dazzle, the big bad, the grouchy potato, the Grinch, if you will.

And these Grinches are mean, they don't talk, they don't mince words. If it's a problem, its gone, pop, blam, kapow. Reindeer, no problem. Some hacker in pajamas, weak! Children? They eat children for breakfast! How does Santa deal with a savvy bad guy?

With medicine

Well, Santa doesn't deliver just toys. He delivers gifts for all sorts of people, including much needed medicine to old folks and sick children. Of course, Santa has this one troublemaker elf who regularly stows away with the gifts, because elves aren't normally allowed to come along, precisely because of pranks like this.

Because there's infinite storage in the sleigh, there's no way Santa could ever find him. So this joker elf loves playing pranks on people, especially Santa, so of course he takes some laxatives which were going to be delivered to the old people's home, and adds it to the mince pies Santa collects from children, which Santa plans to eat later.

Now these aren't your usual laxatives. They're magic. Fast acting. But because the Grinches are thieves, they steal the gifts and the mince pies (it's why they want to get Santa, he has infinite storage and infinite gifts! It's a magic sack that negates weight, quantum physics, that sort of stuff), and of course, to show how evil they are (they don't mess around)... they eat the pies in front of Santa, despite him telling them not to. And there's only one toilet. Cue a fight over who gets to go in first.

So Santa slips away with the gifts to deliver to the rest of the children... he's survived for another year of hijinx at Christmas.

The Conspiracy

It really surprises me to not see the following answer; I think it rather obvious, yet I have to teach it to people each year.

Perhaps you've noticed the ubiquity of Santa? Every mall, every street corner (well, in some big cities) has one. Clearly simultaneously. How might this be? Proxies. Agents. Delegates. Impostors. Embodiments. People willingly possessed by the Spirit of Giving. You get the picture.

Literal appearances by the definite article are agonizingly rare in the days leading up to the big night (he's very busy!), and meticulously planned and prepared for, right? Send an undercover representative! (Sounds a little like the Men in Black, doesn't it?) How can you be sure the same doesn't occur on Christmas Eve?

Consider this: what if duly designated representatives of the Claus Estate do the actual naughtiness judging, procurement, wrapping, and delivery of the end product? I have been cleared by the United States Marines to reveal, but only to other grownups like you, that this is exactly what they've been authorized to do by the franchise owner, his wife, and elfish lawyer contingent. It's called the Toys for Tots™ charity.

And, ultimately, the reason NORAD¹ not only tracks the main man, but broadcasts it in realtime doesn't indicate vulnerability. In fact, it serves as a warning to clear the skies in that area. Anything moving that fast and that 'erratically' (with no radar signature, due to organic material construction) and no running lights would pose a huge danger to air traffic, especially when its not equipped with rated transponder and radio equipment...much less being an unique and experimental flying vehicle (EFV).

It may even be possible that I have been an embedded, vetted proxy of the estate during my decades of being a father. I literally can't say.

¹ Consider this for a moment: who has better qualifications for leadership; a generous, charitable, giving candidate; or a grouchy, mean-spirited, vindictive grinch? Which would the chain of command choose? Surely parties with the resources and opportunities to target the Spirit of Giving would clearly require enough undercover Agents of the Claus, that their efforts would be thwarted from within.

It only looks as if Santa is defenseless. But most of the things that you consider to be part of the lore for fun are actually just well-disguised countermeasures both explicit and innate to him and how he does things.

He's knows when you've been sleeping....etc.

This isn't easy to pull off when there's currently 7.5 billion people on the planet (whether or not they believe is irrelevant), and it's a little-known fact that Santa uses his image as "jolly old St. Nick" to obscure the fact that he has a genius level intellect. This is a crucial compliment to his intelligence network. Coming up with the perfect toy for every human being on the planet has honed his mental aptitude, and over time he's gotten very good at anticipating mere mortal humans. In fact, he's so good that he simply out-gambits most of his potential foes. Sorry, Billy, but Santa's been watching you for a very long time; he saw your path from wooden horse to grizzled mercenary coming before you did. Why do you think you didn't get that pop-gun when you were 8? Don't think you're going to outwit him now.

That 'special dust' you often see in pictures of his flight isn't magic

While pretty to look at, that 'glitter' behind him as is often depicted isn't just for show. It's actually a highly advanced countermeasure that operates on the same principles as chaff. Not only does this make it hard to actually track him (Norad's tracking is just a dog and pony show they put on to keep the US military from appearing ineffective), but several modern surface-to-air attacks are basically useless too. Couple this with flying at night, and anything thrown at him will need to be done blind.

Those cookies have to go somewhere

It's hard to do this job even in the most ideal conditions, so it helps when you have a predisposition to rapid healing. Jagged chimneys, sub-zero temperatures at high altitudes, and active fireplaces are just a few of the hazards you can encounter when delivering toys. Santa hasn't been around for a long time through rigorous attention to his body alone; it's the same reason he seems to be effectively immortal. Of course, you can't just heal out a chance gash or gunshot wound without some help, so he's worked hard to spread traditions like milk and cookies to keep him supplied with adequate caloric intake.

Mutually Assured Destruction

Santa's sleigh has to carry all the toys for all the children in the world, or rather the bag in the sleigh, and it is also magic and has infinite carrying capacity... somehow. Now if we assume that this is merely 1 kilogram of toy per child then that is 2 billion kilograms of presents according to google. Now let's just consider what would happen if it were to fall out of the sky which would occur if Santa's sleigh were to in any way be compromised (such as if anyone were to shoot a missile at him). Let us assume that Santa is over a kilometer in the air. Let us now compute the potential energy due to gravity that the sleigh contains (the mass of Santa and the reindeer is negligible compared to the mass of the presents).

The formula for potential energy due to gravity is $$PE = mgh = 2000000000*9.8*1000 = 19600000000000$$ Joules.

The force would be $$140000000000$$ Newtons assuming the bag takes one second to stop.

Note that the bomb dropped on Hiroshima was 63 TJ which is $$3.2142857142857141217201166180758$$ times the energy of Santa's sleigh when falling. Note that if my estimate on the presents is low and that the average weight is actually $$10$$ kilograms then this is 3 times the energy released by an actual nuclear bomb! Let's for the time being assume continue assuming the former number, though. Anyone shooting Santa out of the sky would effectively be doing the equivalent of dropping a nuclear bomb on their own land, or if hitting Santa over another country would risk triggering World War III and nuclear Armageddon. This also is not at all factoring in the density of Santa's sleigh in terms of what might happen upon explosive decompression. I unfortunately am not greatly skilled in the physics of explosions but I can imagine that a bag hitting the ground at an impact force of $$140000000000$$ Newtons and then bursting open might cause some problems.

I cannot determine the explosive force, but I can attempt to determine the force and velocity of a present as shrapnel. Let us assume that the bag is on its outside $$5$$ meters in diameter. This gives us a volume of $$65.45$$ and a density of $$\frac {2000000000}{65.45} = 30557677.616501145912910618792972 \frac {kg}{m^3}$$. The density of steel according to google is $$8050 \frac {kg}{m^3}$$. For our purposes we will assume that the bag will dilate to that density in a period of $$0.5$$ seconds. That will change the volume to $$\frac {2000000000}{8050} \frac {m^3}{kg} * kg = 248447.20496894409937888198757764 m^3$$ with a radius of $$38.998553782062510720251554279261$$ meters. This means that for a $$1$$ kilogram present it accelerated from initial velocity of $$0$$ relative to the bag to a distance of $$33.998553782062510720251554279261$$ meters in $$0.5$$ seconds. This means that the acceleration can be found by $$33.998553782062510720251554279261 = \frac {1}{2} 0.25*a$$ and so the acceleration is 271.98843025650008576201243423409 meters per second squared. This means the explosive force applied to that present was $$271.98843025650008576201243423409$$ Newtons. Note that if we consider a time of $$0.001$$ which is likely more reasonable we get a force of $$67997.107564125021440503108558522$$ Newtons outward. Note that this will add to the force being applied to the ground which is likely negligible. However, the density of paper is $$250$$ kilograms per cubic meter according to google so in actuality so I am low balling big time. It is worth pointing out that at least everything within a $$100$$ meter radius is going to cease to exist. There are no doubts there. We've already allowed a dilation to $$30$$ meters while assuming the bag contains a pure ball of steel. It is safe to assume that Santa's gift bag being dropped from his sleigh (or even the sleigh losing control) is easily on its own a weapon of mass destruction without even factoring in any release of magical energy from the bag itself in the form of radiation.

This is all just assuming that each child on average gets a gift with a mass of $$1$$ kilogram! If we assume Santa is even more generous and carries $$100$$ kilograms per child or that he carries multiple years of presents in advance then this bag gets even worse and could be more destructive than the Tsar Bomba (largest ever detonated bomb). It wouldn't surprise me if it is heavier in practice than the meteor that wiped out the dinosaurs!

And this doesn't even consider the sheer number of missiles it will take to hit the thing and how much damage those will do when they miss considering how fast he must be moving! After all, those missiles have to go somewhere!

Edit

So it has occurred to me that I never addressed the issue of Santa himself being attacked in person. Well the answer is simple really. Santa is almost always carrying his bag of presents. Now it is a bag of holding. This means that unless it is compromised (see above) it should weigh like any other bag. However, some versions of the notion allow for the user to decide whether it weighs like a normal bag or not. If we assume Santa can allow the weight to "leak" out of the bag, then presumably he can smack someone with the weight of a car assuming that he can lift it.

But that only works in a fistfight or a knife-fight. What if the person trying to kill Santa has a gun and Santa's bag is not in his hands? Then Santa is in big trouble.

However that's until you consider that Santa is delivering to over 2 billion homes in a single night. Let's assume it takes the average person 10 minutes to sneak into a chimney and deliver the presents. If we assume a 24 hour period then it takes Santa 0.0000432 seconds to do the same route. This is 13888888.888888888888888888888889 faster than what a human can do. Note, also that amount of time is slower than human reaction time. This means that Santa can be in and out of most places faster than said armed assassin can pull the trigger. Santa is basically the Flash.

And if we assume instead that Santa simply has time warping abilities and just jumps into the past throughout the night to prolong the time he has to make the delivery, then at that point there is nothing stopping Santa from getting shot by a random grinch. However, does he actually need to prevent that? If Santa has all of this magic and has bag of holdings and time bending powers and can somehow make presents for 2 billion people (or that much coal and likely that much coal since the naughty list takes a while to finalize) then this guy can solve energy problems among many other things. Perhaps the simplest and easiest answer here is that Santa knows magic, and one of the most basic magic spells is healing magic. So if Santa get's shot he just heals himself. If Santa gets stabbed he just heals himself. If someone shoots a rocket launcher at Santa - ok now we're just getting ridiculous.

Nuclear gumdrops.

No, hear me out. In addition to his sack of gifts, Santa carries a bag of perfectly ordinary gumdrop candies in his sleigh: the kind you might use to build a gingerbread house. He probably snacks on some in midflight, but they also represent considerable destructive potential.

Others have already mentioned that Santa has to travel at a respectable fraction of c in order to reach every child's house in a night. There's an interesting WhatIf article that shows what happens to things traveling at relativistic speeds in an atmosphere. Basically, you get nuclear explosions.

In order to protect Santa's sleigh from simply going kaboom, he must have some kind of magic or device that can move the air away from the front of the sleigh. There would still need to be a small bubble of air immediately around the sleigh, so that Santa could breathe, but as long as that bubble continued to move with the sleigh, and did not contact the outside "still air", that wouldn't be a problem.

So some super-missle or something starts following Santa, and he tosses a single gumdrop out the back of the sleigh (let's assume the gumdrop weighs about 10 grams). It would pass out of the air envelope with no problem (since it's still not moving very fast relative to the sleigh and the bubble), and likewise through the airless field (since there's nothing to collide with). But then it slams into the relatively still atmosphere at, in that atmosphere's frame of reference, relativistic speeds, and kaboom. My numbers are extremely hasty, but the resulting explosion should have roughly as much energy as 1 ton of TNT: in other words, plenty of firepower. If something were to get into the airless field, then Santa would actually have to hit it with the gumdrop, but if he managed, the effect would be more or less the same.