First Form:Caterpie A quiet pokemon who loves Shan because she saved its life. Shan thought that Caterpie was to week to battle so she didn't use it in the fight with the Ratakate or with the First fight with team Rocket. When it saved her from Tachi in the restaurant Shan realized that it was more powerful that she thought.
Second Form:Metapod. Ok it's a cocoon. It doesn't do much. Shan doesn't want to battle Metapod. She is afraid that if it gets hurt it won't evolve into Buterfree. Since Caterpie was a bug it evolved faster than other pokemon normally do. Metapod helped Shan beat Steels' Onyx. The Onyx gave up just before Metapod ran out of strength to Harden.