Puck is a supporting character in the Dragonball GT movie A Hero's Legacy as well as in Dragon Ball AF, fighting as a member of the Dragon Team. He has two faces in the movie, bullying Goku Jr in the first half and becoming a good friend of him in second half.
Dragon Ball GT
A Hero's Legacy
He is first shown in the school playing for which he is condemned by the teacher. Later he is shown several time bullying Goku Jr, the most memorable being the one in which he steals away his Rocket Pen.
Later his view towards Goku Jr changes and he accompanies him towards Mount Paozu. In the way they spend a lot of time discussing about one another and Puck enventually returns the Rocket Pen back to Goku Jr. They both fight against Mamba, a cannibalistic witch to save themselves.When Goku Jr who was hanging from a single rope due to the hanging bridge's collapse Puck nearly gives up his own life in an attempt to save Goku Jr. In the end both of them meet, when Puck and Pan flies from an helicopter due to utter resilience of Goku Jr who was keen to bring his grandma and friend back to life. Puck may be related to Uub.