Metapod

Metapod is the second stage of evolution for Caterpie. Metapod are vulnerable to attacks while their shells are soft, exposing a weak and tender body. In "Challenge of the Samurai", Ash's Caterpie spins its first cocoon and evolves into the oddly shaped Metapod. The gang then encounters an ominous young samurai out to prove his worth as a Pokemon trainer. It's Metapod against Metapod as the two masters-to-be unleash their contestants to prove who is the greater Pokemon trainer. Metapod, Go!

First appearance: Episode 4—"Challenge of the Samurai"