Known as the Cocoon Pokémon, are pupal Pokémon found in the wild early in the Kanto and Johto regions, of which its larval form is the caterpillar-like Caterpie. They can evolve into the butterfly-like Butterfree. While Metapod is classified as a cocoon Pokémon, it bears more resemblance to a chrysalis. A Metapod's exterior is regularly hardened to protect its soft and tender innards while undergoing metamorphosis to eventually become a Butterfree. To conserve energy for this event, the Metapod barely moves. While this shell is said to be as hard as steel, a large sudden impact could cause its vulnerable body to pop out, leaving it completely exposed.