It evolves from Caterpie starting at level 7, and it evolves into Butterfree starting at level 10.
While Metapod is classified as a cocoon Pokémon, it bears more resemblance to a chrysalis. Its soft body is protected by a hard outer shell while it undergoes metamorphosis. 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. It shares many physiological and behavioral characteristics with Kakuna, Silcoon and Cascoon suggesting a possible relation between the four.