So in the Marvel universe, the Incredible Hulk is a "hero" that looks like a normal dude until he gets angry and becomes a huge green monster.

Ignoring the fact that the way he became the Hulk would have killed him (look it up if you don't know), how would a human metabolism keep up with the muscle growth alone (bonus points if you can have him ready to rampage in seconds)?

Some possible things that might help: The green color could be chlorophyll and could collect energy passively.

When our "hulk" slims back down he could reabsorb the extra muscle mass to help with recovery.

I would like to see the resulting creature be able to blend into a human society (as a human) so adding a camel-like hump to store extra calories would possibly allow the hulk to pass off as a hunchbacked hermit.

Due to lack of matter/energy i am going to allow some light magic that lets him absorb matter around him to fuel his growth. I would prefer not to use this but if that is the only way, I guess that's fine.

  • 2
    $\begingroup$ Chlorophyll is inefficient enough that it wouldn't help the energy equation, sadly. There really isn't any "human" metabolic pathways that would enable something like this to exist within a reasonable time frame. $\endgroup$ Mar 16 '15 at 19:21
  • $\begingroup$ The short answer is, it can't. There's nowhere to get the extra muscle mass from. $\endgroup$
    – KSmarts
    Mar 16 '15 at 19:22
  • $\begingroup$ I'm waiting to see how anyone deals with the extreme violation of the conservation of matter/mass here. $\endgroup$ Mar 16 '15 at 19:22
  • $\begingroup$ Related: scifi.stackexchange.com/questions/5814/… $\endgroup$
    – KSmarts
    Mar 16 '15 at 19:33
  • $\begingroup$ Try looking at this question/answers for werewolves.worldbuilding.stackexchange.com/questions/449/… $\endgroup$
    – bowlturner
    Mar 16 '15 at 19:49

Without magic, or magic-level technology (Clark's 3rd), this is not possible. The Hulk is a gross violation of conservation of mass. In short, unless he had the ability to generate matter from raw energy, he could not alter his own mass on the fly like that without high-level magic.

If we use Marvel's Hulk as an example...Bruce Banner weighs 200lbs. The Hulk weighs (low end) about 1,040lbs. Obviously, we are missing 840lbs (381kg) of mass that had to come from somewhere.

If we allow him to convert energy into mass to turn himself huge, then using our good buddy


we can figure out what it would take. In order to produce 381kg, Hulk needs to convert

$$3.4243 * 10^{26} Joules$$

into mass, which is equivalent to 8184.2 Megatons of TNT. For reference, the biggest explosion made by man was only 50 Megatons. For further reference, in 2008, the entire world only used

$$4.74*10^{20} Joules$$

Meaning that in an entire year, the world only consumed .00013% of the energy The Hulk requires for a single transformation. This would be the single most energetic event to have ever occurred on Earth. (outclasses the Chicxulub Impact by 1000x) There is simply no biological way that this could happen. Even the 'official' explanation put out by Marvel fails to work with Physics. And, of course, you have to deal with a discharge of that much energy whenever he shifts back. In short...if he shifted, he'd cause an apocalypse from sucking up that much energy. Then when he discharged the energy, he'd blow a very sizable chunk out of the planet and probably sterilize it in the process.

If you are willing to roll in hand-wavy magic...then it could be possible that this extra mass is stored in an extra-dimensional pocket, which he can retrieve when necessary. Or maybe 'mana' can be converted into mass at a higher efficiency than energy.

  • $\begingroup$ Note: If you are okay with him weighing half a ton while in human form (is NOT going to pass for a human) then this might be a little more doable. But mass changes tend to have apocalyptic consequences. $\endgroup$ Mar 16 '15 at 19:59
  • $\begingroup$ Actually the whole draining the world of energy and then exploding all over the place is kinda cool. I may use that as a doomsday weapon. $\endgroup$
    – unknown
    Mar 16 '15 at 20:05
  • $\begingroup$ oh, and all that mass you create? It would also generate an equivalent amount of anti-matter. BOOM $\endgroup$ Mar 16 '15 at 22:32
  • $\begingroup$ Sigh. Why are the possibilities of all that atmosphere the guy is standing in neglected so often? Where do trees get their mass, after all? The ground? No, for the most part: The air, from carbon dioxide. It would require greatly less energy to bind atmospheric matter than to transform energy to matter directly. $\endgroup$
    – Monty Wild
    Mar 19 '15 at 0:05

Few possibilities (some are rather silly but might fit your requirements):


The Hulk could actually be less dense than a normal human. So instead of actually adding mass, hulking up is more like inflating a balloon.

This causes several undesired side effects - for example, he will now blow away in a strong wind - so you need to address that with secondary effects. Perhaps he manipulates his internal Higgs Fields to increase the effect his mass has on the environment, giving him an effective and measurable weight of ~1 ton without actually increasing his mass.

Temporal Storage

Maybe he steals it from himself. Bruce Banner might need to eat 10,000+ categories a day, without gaining any appreciable weight. That extra mass is then consumed by future-Hulk the next time it transforms, both to bulk-up and to help power the transformation. Since the transformation goes back in time, he doesn't actually store any extra mass at that time.

As a side effect, he will gain a massive amount of weight if he's set to die in the future before he transforms again, since no future consumption is occurring.

Parallel Dimensions

These are a staple of a lot of superhero stories. Let's say that Banner is transformed 1% of the time. If there are at least 100 parallel universes, then the extra mass of the Hulk can exists in at least one universe at a time, transferring between universes as required.

Because this would put strict limits on when he can transform, it would be best to have a large - potentially infinite - number of universes, each temporally offset slightly. That way the Hulk Mass usage will average out and he'll be able to transform basically whenever he needs to.

Parallel Dimension 2

The "Hulk" body isn't actually a transformation. It's war chassis from another dimension, and the entire body gets stored when not in use. Long ago a super-advanced race set up these Hulk Bodies as war machines, and they transferred to them in combat. Bruce Banner never actually transforms - instead the gamma ray exposure accidentally gave him access to a specific Hulk War Body. Humans weren't designed for these bodies, and he wasn't prepared for the transfer, leading to uncontrolled trigger issues and his anger management problems.

The appearance of a transformation is actually an undesired result of an over-enthusiastic programmer of this old super-advanced race, who wanted it to look cool when he switched to his war body.


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