Butterfree was encountered at Vermilion Forest. He was found resting on a large tree, which Go climbed with Ash's help. When Go accidentally dropped his Poké Ball, Butterfree attempted to flee, but was caught when Scorbunny kicked the Poké Ball at it. Butterfree and the rest of the Kanto Bug-type Pokémon Go caught were brought back to the Sakuragi Institute where Professor Sakuragi kept them in storage for Go.
None of Butterfree's moves are shown.