Another crazy story. Another crazy idea I want to realistically implement.

The protagonist in this case (Ryker) just entered a mysterious, abandoned, but actually very boring "diner" with almost nothing in it. (Five tables in the center of the room, a chair on each side, a counter with the cash register with a menu above that and a door to the backroom beside the counter like the front of a restaurant interior).

After finding a key next to the cash register, he managed to use it and ended up blacking out from the resulting shock. With me so far? Because it only gets worse I'm afraid. You see, when he wakes up, Ryker has changed drastically.

Ryker is a teenager. Sixteen years old. About five feet tall. But, that key and the shock it gave him somehow triggered a rather implausible transformation. Think 'teenager-who's-in-okay-shape' to 'adult supersoldier'. He's gone from teenage proportions to adult proportions. Maybe not the biggest change in the grand scheme of Mother Nature, but with that kind of change happening overnight, he should notice something!

That's about a foot of height (he was five something, now he'll be six something), a drastic increase of muscle mass (and a increase in overall mass), slightly increased proportions....teenagers are kind of small adults, especially about halfway through, so it's not quite as drastic as tween hiccup turning into 20-year-old hiccup from How To Train Your Dragon 2, but it's still a big jump. And in the story, he just woke up.

The question is, Will he notice anything?

Specifications of scene:

  1. Strangely enough, the room has no dust or clutter. (Yes, there is a reason. Yes, Ryker noted that was strange.)

  2. There is no noticeable effects to senses or metabolism. He is not going to wake up hungry. He is not going to talk to himself because he has "oh-my-gosh-I-passed-out-in-this-strange-building-and-its-morning-I-still-have-school" and his reaction will not be metacognition. He may notice the slight change in his environment, especially after he starts running to school, but maybe not. He'll be distracted, after all. And the environment is such that he can't detect the change that way (no mirrors, no reflective windows).

  3. Despite the drastic changes, Ryker's body will have pre-adjusted. He won't feel a difference as he gets up. And his clothes transformed with him, so he won't figure that out from that either.

That's basically it I think. I tried to cover everything, but likely missed something. If this is the case, please let me know, thanks!

  • 2
    $\begingroup$ @sphennings: I think of it more like "Bob shrunk alice. Will alice notice?" Similar situations even. $\endgroup$
    – Alendyias
    Jul 24, 2022 at 0:34
  • 2
    $\begingroup$ @sphennings: the exact title is "Alice has been shrunk! Will she notice?" $\endgroup$
    – Alendyias
    Jul 24, 2022 at 2:11
  • 21
    $\begingroup$ "Teenager increased to adult proportions // Ryker is a teenager. Sixteen years old // That's about a foot of height (he was five something, now he'll be six something)" I believe your proportions may be seriously out of kilter with our normal real reality there, many (if not most?) teenagers have already practically attained their full height at that age, iirc I don't think I had more than an inch or two at most left to go of my final just shy of six foot at that age, certainly it was nothing like a significant proportion of a whole foot. $\endgroup$
    – Pelinore
    Jul 24, 2022 at 5:46
  • 4
    $\begingroup$ Does it really have to be such a significant change? Age 14, I was 5'8" and weighed 150 pounds. When I joined the Navy at age 20, I was 5'11" and weighed 150 pounds. $\endgroup$
    – WGroleau
    Jul 24, 2022 at 20:47
  • 5
    $\begingroup$ You may want to reconsider his height, as 152cm (5ft), is below the 1st percentile for a 16 year old, an average 16 year old would be closer to 172cm (5'7"/5'8") (Source: WHO Average Height Chart). Also as mentioned above, there is not much growing left at 16; the average height for boys increases by 3.6cm (1.4 inches) from 16 to 19 $\endgroup$
    – B-K
    Jul 25, 2022 at 2:25

5 Answers 5


The world feels notably different when you're stronger.

Doors slam a lot more easily, you can jump further, and things break in your hand. This is gonna be pretty obvious quickly.

We notice deviations in our bodies pretty fast.

If he's running around he'll see his arms. If they're suddenly jacked, he'll see that.

Objects will be in very different places and he'll need to adjust his actions to handle them.

Door knobs and light switches and lots of stuff is gonna be in a different place, which is pretty obvious. Try getting a stool a foot tall and standing on it. The world looks radically different.

He'll need to relearn how to walk and move.

This will be a pretty large difference. He's much stronger and taller. His limbs will move weirdly. If he moves quickly, even if there's some adaption he's likely to fall over.

Yes, he would likely notice.


His clothes will be very tight.

Shoes might be ok. Feet get a growing head start. But if he has bulked up that much, shirt and pants will be tight. Maybe he will be busting some seams. Split pants is not a great look as you no doubt have learned from hard experiences. But tight teenager clothes could be a good look for this dude if his clothes are made of stretchy material. Jacked supersoldiers in tight clothes can get some love from the ladies. Or supersoldier loving persons of any persuasion because it is a new millenium we are in!

  • $\begingroup$ Oh sorry! That's the one thing I missed as I edited and reedited the question before release! The clothes transformed with him! I hope this is no terrible inconvenience.... $\endgroup$
    – Alendyias
    Jul 23, 2022 at 23:49
  • 1
    $\begingroup$ @Alendyias - I am ok with it as long as they transformed into a shimmering gold lamé jumpsuit and green adidas. It seems a waste to have transforming clothes if they just go from a M to an XL Yu-Gi-Oh T shirt and your same sweatpants but bigger. $\endgroup$
    – Willk
    Jul 24, 2022 at 0:30
  • $\begingroup$ Oh, it'll be fun. For this story they'll transform into essentially an adult supersoldier body with sleek black body armor. And if you think that's crazy, later on they'll accidentally summon a sword and shield made of what appears to be glowing plastic when they end up facing a dinosaur. $\endgroup$
    – Alendyias
    Jul 24, 2022 at 0:33
  • 2
    $\begingroup$ Man, I wish I could upvote this more than once. Let's pretend the kid's wearing the ubiquitous skinny jeans. He'd have about two minutes to get those things off (and, plausibly, the tightie-whities) before cutting off enough blood flow to his brain that he'd pass out and die. That's assuming he wakes up immediately after the transformation. And it's assuming he survives the adrenaline panic. $\endgroup$
    – JBH
    Jul 24, 2022 at 20:26
  • 1
    $\begingroup$ @JBH - the transformation scene in Captain America would have been a lot more compelling if the first thing he did was rip off his tightie whities. Bruce Banner solved that problem by always wearing big cutoff jean shorts under everything else. $\endgroup$
    – Willk
    Jul 24, 2022 at 21:44


Because he's dead. You said you wanted realistic. There's a reason most story McGuffins are left unexplained.

In your case...

  • Body mass doesn't magically appear. If the child's body is suddenly 20 pounds heavier, those 20 pounds came from someplace. If the body suddenly grew as much as you explained without those 20 pounds being somehow injected into the body, then where they came from was the body itself. This is called Catabolysis. Unless, of course, from the perspective of suspension-of-disbelief (NOT realism) your boy is a big old fatso. In other words, your morbidly obese 250-pound sixteen year old becomes a 250-pound Captain America. (Why is this not realistic? Because you can't get bones and muscles from fat... everything you need isn't there.)

  • I've gotta point to @WillK's answer and point out the problem with kids wearing skinny jeans. No blood flow to the brain post-change. Dead adult wearing a sixteen-year-old's skinny jeans with burn marks on his thumbs and fingers where he was trying to pull the denim against the force applied to the button.

OK, but let's throw "realism" out the window and assume he survives... Would he notice anything?

Uh, yeah...

To quote the adroit Mr. Data from Star Trek:

My legs are exactly eighty-seven point two centimetres in length. They were eighty-seven point two centimetres the day I was created. They will be eighty-seven point two centimetres the day I go off line. (Star Trek: Insurrection)

Your brain is wired to deal with where everything on your body is. It changes that perception as the body changes—which is slowly. And even then, because things are changing, gangly teens will trip over their own feet! (Thus, the quote where Data's asking a child how he deals with the changing length of his legs.) The child would awaken and suddenly have trouble standing up, grabbing things, walking, even ducking to avoid things near his head. It would take time for the brain to adjust to where "everything is" again.

Worse, the child's view of the world would change, too. Why did everything look bigger when you were a child? Because your perspective was from that of a short being. You had to look up at a lot of things. Granted, a sixteen year old is closer to adult height than a five-year-old. But the problem would still exist. Things that the sixteen-year-old didn't bother ducking for suddenly require ducking. And he won't until he gets used to the new perspective. Ask yourself, if you stand on the rung of a ladder or upon a step stool, do you not notice the difference in perspective? Yes you did, you're just not paying attention. My point is, the desk top would suddenly look like he was standing on the bottom rung of a ladder. Yeah, he'd notice.

And that's ignoring @NepreneNep's completely valid point that the change of strength would be completely noticeable. To the point where the first time he tried to pull out a drawer I could believe he'd throw it half-way across the room.

Reality is over-rated, just do it

You asked us to come up with a way that, "realistically," a child could instantly or near-instantly gain the body shape of an adult and not notice it.

Yeah. Not gonna happen. Maybe if he was locked in a sensory deprivation tank filled with nutritious fluid, and even then maybe not (it would drain volume from the tank to make the body bigger... and heavier... which he'd feel on his shoulders and hips...).

Therefore, I'd like you to consider changing you frame of reference. Stop thinking that you need to create fiction in a way that's "realistic." Realistically, what you're trying to do isn't possible or plausible, so no wonder the results you're looking for are kinda... well... impossible or implausible. Rather, you should shift to "suspension of disbelief." You'd be surprised how much belief people are willing to suspend for the sake of a good story. After all, we were willing to believe that a gallon of red punch and semi-mythical "vita-rays" brought about similar results for Captain America. Heck, if Haley Atwell's in the story, I'm willing to believe almost anything.


Part One: Height Advice.

When I first read the question title, I wondered what difference there would be between the size of a teenage boy and the size of a full grown man. When I read the boy Ryker described as being "Sixteen years old. About five feet tall." I thought that was very improbable.

Other people have also commented that Ryker's age and size seem improbable to them.

I later remembered the great differences in the growth rates of various children and that the growth rates which were familiar and normal to me were not the only possible growth rates for boys.

If Alendyias is from a time and place where it was normal and common for boys to be "Sixteen years old. About five feet tall." and so thinks that is the normal size for boys that age everywhere and every time, maybe they should set their story in that time and place, or select another time and place when and where it was common for sixteen year old boys to be about five feet tall.

And before Ryker has his magical instant growth spurt, Alendyias should show the readers that most sixteen year old boys there are only about five feet tall. Possibly a boy at school should be described as being almost six feet tall and a giant standng head and shoulders above the other sixteen year boys in the class. Perhaps Ryker's height will be measured some time befor he grows.

And Alendyias may need to state that it was normal then and there for Ryker and other sixteen year old boys to be that small.

In most societies there is a considerable spread in the rates of growth of boys and the heights of boys at the same age. And there is also a considerable spread in the rates of growth of boys between different societies at the same era, or between different eras of the same society.

Robert Pershing Wadlow (1918-1940) was the tallest medically record human, reaching a height of eight feet 11.1 inches. At the age of 16, he was eight feet 1 1/4 inches tall. https://en.wikipedia.org/wiki/Robert_Wadlow

The shortest medically recorded man was Chandra bahadur Dangi (1939-2015) of Nepal, at 21.5 inches or 1 foot 9.5 inches. https://en.wikipedia.org/wiki/Chandra_Bahadur_Dangi I find it easy to believe he might have been a couple inches taller at age 16 then when his age was measured as an old man, but I doubt whether he was ever much more than two feet tall.

Even among normal sized people without any medical conditions affecting their growth, probably at least one percent of normal growing boys will be at least ten percent taller or shorter than most boys their ages in their society.

Part Two: Some personal examples.

I remember that when I went to high school most of the boys in my class grew to close to their final adult heights, maybe five feet eight or five feet ten inches tall, when aged fifteen or sixteen. I guess I reached about five feet nine or ten inches when I was fifteen, and considered myself to be almost six feet tall.

I remember when I saw Shenandoah (1965) an early scene had the Anderson family at the table. The imaginatively named "Boy" Anderson was asked how old he was and said eighteen, but his father said he was sixteen. And since I think he was about five tall I thought he looked more like a twelve year old boy to me.

Actor Philip Alford was born September 11, 1948 according to IMDB https://www.imdb.com/name/nm0019221/?ref_=nv_sr_srsg_0 And the filming period for the movie included 11 August 1964 https://www.imdb.com/title/tt0059711/locations?ref_=ttrel_sa_4 when pHilip Alford was 15 years and 11 months old.

There were thirty four boys in my small class when we graduated. A few of them were shorter than most. In one of the pictures for the yearbook in the year we graduated, when we should have all been eighteen, the smallest boy in my class is standing next to me. I once measured that photo and found he was a little more than 0.9 times as tall as me. Since I should have been about five feet ten to six feet tall, that boy should have been about five feet three inches to five feet five inches tall when he probably should have been eighteen years old.

A few months after the yearbook photos were taken, I saw a boy, whose age I wasn't told, who was inches taller than me. Standing beside him gave me the creeps because of how cute and young he looked. It seemed unnatural, like he was a young child who had been enlarged by a mad scientist. This boy was inches over six feet tall, and possibly younger than sixteen.

In 1994 I went to a diner in a small village in southeastern Pennsylvania to pick up lunch. And, probably in the summer, there was a boy working there who was about five feet tall and looked about twelve years old. He was blonde, and as cute as most twelve-year-old child acters - I guesss he was approximately as cute as Chad Allen who was born June 5, 1974 https://www.imdb.com/name/nm0020354/?ref_=nv_sr_srsg_0 at the age of twelve, like in the first season (1986-87) of Our House.

ONe evening I was having dinner at a restaurant in that village, and that boy was one of the waiters who brought our dinner. One of my companions asked if he was old enough to work there. He said yes, he was sixteen. And my companion quite understandably said: "I don't believe you! You're so cute! you look like your twelve! You're so cute!".

Of course there are exceptions to age limits for children working in the family business, but would two different places in the village be operated by the boy's family? And I think he would have had to be age sixteen to work in a restaurant that sold liquor. Certainly nobody would take his word that he was sixteen but would demand documentary evidence to show to restaurant inspectors.

The Swiss actor David Bennent, born September 9, 1966 https://en.wikipedia.org/wiki/David_Bennent, is famous for the role of Oskar in The Tin Drum (1979), but I remember him as the elf leader Gump in Legend (1985). Legend (1985) should have taken a couple of months to film, but has a filming date of 24 March 1984 in IMDB, when David Bennent would have been 17 years, 6 months, and 15 days old https://www.imdb.com/title/tt0089469/locations?ref_=ttrel_sa_4. But Gump looks about five feet tall and about twelve years old.

Part Three: Some Historical Examples.

Here is a link to a story about Adolf Hitler's last public appearance https://historyofyesterday.com/alfred-zech-18a89a8d4ae6, decorating soldiers on 20 March 1945. Alfred Zech, the small boy wearing a black uniform in the photos, was born 12 October 1932 https://en.wikipedia.org/wiki/Alfred_Zech, and so was 12 years, 5 months, and 8 days old. And the boy in a grey uniform beyond Zech isn't noticeably taller. That boy was Willi Huebner (1929-2010) https://rarehistoricalphotos.com/wilhelm-willi-hubner-1945/ who should have been 15 or 16. In the photograph with Artur Axemann, the top of Hubner's helmet is level with Axemann's shoulder.

Sabu Dastigir (27 January 1924-2 December 1963) was a child star. https://en.wikipedia.org/wiki/Sabu_(actor) The Drum or Drums (1938) was first released on 7 April 1938 https://www.imdb.com/title/tt0030082/releaseinfo?ref_=tt_ov_rdat when Sabu was 14 years, 2 months, and 11 days old, so Sabu should have been thirteen when it was filmed. Drummer boy Bill Holder (Desmond Tester) always looked approximately the same size and age as Sabu's Prince Azim to me, but Desmond Tester was born February 17, 1919 https://www.imdb.com/name/nm0856469/?ref_=tt_cl_t_6 and so was eighteen when the movie was filmed.

I have measured my head with a ruler and a mirror as being 9 inches tall. Assuming that most people should have heads that tall by the time they go to school, the heights of people in old phtographs can be measured using their heads, among other items in the photos.

King Edward VIII of the UK (22 June 1894-28 May 1972) came from a wealthy family who could afford to keep their children well fed.

In this picture https://en.wikipedia.org/wiki/Edward_VIII#/media/File:Prince_of_Wales_9.2_inch_gun_HMS_Hindustan_Flickr_4454627308_cd3c9739e8_o.jpg of Prince Edward as a midshipman on HMS Hindustan in the summer of 1910, about the time of his 16th birthday, he appears to be about 6.4 times as tall as his head, though his cap makes it a little uncertain. That should make him about 57.6 inches, or 4 feet 9.6 inches, tall.

He was invested as Prince of Wales on 13 July 1911, aged 17 years and 21 days. In this photo of him in his regalia as Prince of Wales he appears to be about 6.4 times as tall as his head, or 57.6 inches, or four feet 9.6 inches, tall https://www.alamy.com/stock-photo-the-prince-of-wales-later-king-edward-viii-in-his-investiture-robes-37418803.html.

In this photo from 1920 https://www.posterazzi.com/the-prince-of-wales-later-king-edward-viii-in-1920-edward-viii-edward-albert-christian-george-andrew-patrick-david-later-the-duke-of-windsor-1894-posterprint-item-vardpi1957746/, when aged 26, he appears to be roughly about 7.5 times as tall as his head, or about 67.5 inches, or five feet 7.8 inches, tall.

According to this site https://www.celebheightwiki.com/duke-of-windsor Edward VIII was 5 feet 6 inches tall at age 78, so maybe taller as a young man. That indicates my photo measurements were fairly accurate, and that he grew a lot after his sixteenth & seventeenth birthdays.

Here is a link https://www.loc.gov/resource/ppmsca.34478/ to a photo of General Grant's cavalry ecort at City Point, Virginia, March 1865. The five bugler boys on the left look about ten to twelve years old to me. But this photo is reproduced in the multi volume Photographic History of the Civil War (1911), and i think I remember the caption describing the bugler boys as being fifteen and sixteen. That gives the impression that it was rather common in 1865 or 1911 for boys those ages to be only shoulder high to men.

Here is a link to a photo of General Custer's staff at Winchester, Virginia, December 24, 1864. https://www.flagcollection.com/tour_listview.php?CollectionTour_Code=groupings_custer

The soldier on the far left behind the flag lance is said to be Bugler Joseph Fought. According to his military records Fought enlisted in 1860 aged fourteen and four feet eight inchs tall, again in 1865 age 19 and five feet three inches tall, and again in 1868 age twenty two and five feet eight inches tall, thus indicating that he grew a lot after his nineteenth birthday and was quite small when he was sixteen.

And my reading about teenage civil war soldiers indicates that many of them were quite small for their ages compared to boys those ages that I knew.


So if Alendyias allows for the fact that most contemporary persons think that five feet is very small for a sixteen year old boy, and convinces them that it is a normal height in the time and place the story is set in, thereis no problem with making Ryker siteen years old and about five feet tall.


...yes. If I can notice a few pounds of bloating after I eat Chipotle, he will have no difficulty noticing this. Even if the height difference stays realistic (an inch or two), he will very quickly notice the whole skinny kid to super-soldier transition.

Probably the first thing he will visually notice is that the muscles in his arms have changed, particularly wrists and forearms since they are usually more exposed. My guess would be shoulders and abs next, based on most guys seem to be self-conscious about these areas. By then he should have caught on and will quickly realize that his whole body has changed.

If you stick with the crazy height change (which is, truly, Alice-in-Wonderland crazy) and he somehow manages to not notice everything else (perhaps this change caused some kind of brain trauma), he will certainly notice being able to reach a lot of things that he couldn't before. Not just tall things, but anything where you have to lean and reach. About half of his height will be in his torso and his arms will be longer as well. (Of course, his arms won't fit into tight places that previously would have been no problem, but at least he can get to the top shelf now.)


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