In this historical-fantasy scenario, a major protagonist has been given the ability to transform into every animal species that Earth has and had offered, alive and extinct. (Which means if he wants to be a T. rex or a Quetzalcoatlus in a medieval landscape that has no knowledge of their existence, he can.) He can only transform into himself and himself as the other species, so spying around disguised as someone else is impossible. (Further clarification, a shapeshifter named "Bob" can't transform into his next door neighbor "Kevin".)

What other side effects would shapeshifting put on the protagonist?

  • 2
    $\begingroup$ Good foundation for a question! Please give us something to work with! This is one of those "infinite list of things" questions that needs to be narrowed down and put into focus for it to be a useful query. VTC $\endgroup$
    – elemtilas
    Aug 22 '21 at 12:15
  • $\begingroup$ Asking about "other" side effects when the question does not present any side effect is lazy. $\endgroup$
    – AlexP
    Aug 22 '21 at 13:37
  • $\begingroup$ Are we breaking physics here? If man becomes Brachiosaur, does he get to more or less float gently above the landscape with the occasional upthrust or is he Brachiosaurus weight? If a flea, does he sink into the ground? Does he burn energy at the rate of the respective animal's rate, or just a human? Does his brain shrink to fit the new skull - ie. does he lose smarts? $\endgroup$ Aug 22 '21 at 13:54
  • $\begingroup$ Could you explain how shapeshifting works and what are the limits of this ability? $\endgroup$
    – Otkin
    Aug 22 '21 at 17:23
  • $\begingroup$ It might be better to elaborate a bit on how it works. Is it magic ("well you see there's an explanation but you wouldn't understand it even if I tried " also counts) or biological (as in he needs to change into something the same weight, and he'll cook up if he changes too fast so it takes a lot of time)? Are the effects of mass shifting and size shifting notorious? By changing into his version of other creatures, does he keep his human knowledge or does his entire brain capabilities also convert into the other creature's? The wording can allow for a lot to be supoosed. $\endgroup$ Aug 22 '21 at 17:46


A shapeshifter can use this to a great advantage. Imagine a virus or bacteria infecting you. It's bad, because you're the optimal conditions for this virus or bacteria to spread.

And then you change the game.

Change into a creature that is unaffected by that particular virus or very good at beating the bacteria. Cold-blooded, warm-blooded, living together with it (bats!), having crude but effective immune systems, or simply being slightly different can turn the tide in a short time. Very few sicknesses or parasites can get a hold on you.

Healing damage is also easy, as you morph anyway. With such drastic changes, healing a wound at the same time seems trivial.


The psychology seems to be the greatest problem. How do you change into something else without losing brain power? Humans are the pinnacle of intelligence, understanding, planning and memory. Changing to a tiger will make you stronger, but jow can you still remember to tie your shoes? Taking the brain power with you is a difficult task, as the human brain is specifically grown in a very large head. Cramming that in other species that are certainly not optimised for it can lead to major problems.

If this is solved, you still need to grow a lot of muscle menory. Sure you can probably grow it that normal walking, running, flying or whatever is required works, but you'll not be optimised. Imagine changing into a human and be presented cutlery. Could you really use it? I mean the first so many times I was eating with sticks was incredibly challenging. That and a thousand tiny things are learned in years growing up. Changing into different creatures will mean you miss all that. All creatures you control will be basic in that control sense.

Finally you might lose identity. Who you are and what you are keep us grounded. If you change regularly, you need to have a special kind of mindset to not go completely bonkers.


How far does the change go? Where do chemicals and nutrients go? If you eat grass as a cow, what will happen to the food in the 4 stomachs when changing? Where does the venom of a snake go? What happens to the dead stuff like hair and nails when changing? Where does extra mass go, or if you don't have enough? How do you power all this? Much can easily be handled by suspension of disbelief, as these kinds of strange things happen in fiction all the time. Yet it us worth mentioning.


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