Fofo was the very Castform that Sapphire saves from a broken water fountain, it was originally Mr. Stone's Castform. It got sucked into the water fountain during his daily stroll around the city when Team Aqua cut off the bars of the pump of the fountain. During Ruby's fight with his father, Castform saves both their lives by using Sunny Day in order to dry up the wet branch that Norman was barely holding onto to avoid them from falling into a pit of broken glass next to the Weather Institute. It also got worried about Ruby after he cries himself unconscious after fighting with his Feebas, so it decides to go with him after Gabby assures it that Mr. Stone would be fine with it going with Ruby since he is in a comma, therefore cannot take care of Fofo.It later replaces Ruby's Ralts in the Smart category of the contests since Rara was still with Wally.
- In the Chuang Yi translation, Fofo was known as Popo.