Dragon Ball Z: Cooler's Revenge (1991)

On Earth, Goku and his friends are enjoying their camping trip when a group of mysterious enemies appear and fight them. After the battle, Frieza's brother, Cooler, appears. He easily defeats Goku, but loses sight of him during the battle, and sets out with his henchman on a manhunt and has his revenge. This film is set at the beginning of the Android arc when Goku, Piccolo, and Gohan have begun their training.