In Vs. Marill, Marill appeared with Lyra when they pulled Ian out of the water. It later was used to battle against Elise and her Horsea. It is fast, hitting Horsea a few times before it can even move. Horsea makes a come back, and Marill is defeated.
In Vs. Weezing, Marill is chosen to use its sensitive hearing to track down the stolen starter Pokémon.