Butterfree

Stage three of this Pokemon's evolution is the most gracious of all as the awkward shell of the Metapod bursts open and the brilliantly colored creature reveals itself to the world. In battle, Butterfree can flap its wings at high speeds to release highly toxic dust into the air. After Metapod sacrifices itself to save Ash from an attacking Beedrill in "Challenge of the Samurai," the eager trainer's innocent Metapod is ripped open by the Beedrill's stinger and a Butterfree is revealed. A dream realized.

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