Catterpie is a caring innocent child cared for by Butterfree but got in danger by falling into a fissure as Milo and Riley rescued the Catterpie in Tiny Woods.  After the Catterpie is reunited with his or her mother Catterpie is really interested in Milo and Rileys adventure they are going on and gives them the package of stuff Butterfree made for Milo and Riley

Catterpies personality he is very curious about learning new things in the world and is inspired by Milo and Riley that they want to become a rescue team.