18. The Axototl
In The Amazing Spider-Man, Curt Connors uses lizard DNA to regenerate his lost arm, and everyone lived happily ever after! JK. Even so, the idea of replicating the reptilian ability to re-grow lost limbs in humans has been a fascinating topic for some time. But the real kings of regenerations aren't lizards at all — they're amphibians known as axototls. These incredible animals can not only replace injured limbs, but much more complex organs, like eyes, lungs, hearts...even their brains! They can also perform head transplants with other axototls, which seems like a very handy superpower. Instead of exchanging friendship bracelets with your BFF, why not swap heads for the day?