Dragon Ball GT (Dub) Episode 16.5

Goku, the hero who destroyed the evil of Frieza, Cell, and Buu in DBZ, learns that an old foe, Emperor Pilaf from DB has captured the 7 magical Black Star Dragon Balls, which, at the cost of the planet the balls are on, can grant any wish. Pilaf wishes that Goku is a child, and Goku becomes a child. In order to save both the planet and restore Goku to adulthood, Goku must allign himself with Trunks and his granddaughter Pan to find all 7 Balls all over the universe. Over time, they encounter foes like Baby, Super 17, and the invincible Shadow Dragons.Taking place 10 years after the final Dragonball Z story, Pilaf finally manages to get all 7 dragonballs and makes a wish. Unfortunately for Pilaf, he gets flustered by the presence of Goku and wishes for Goku to be a child again so that Pilaf could "teach him a lesson." Pilaf gets his wish, and Goku is off on an interstellar trip to gather the 7 "Black Star Dragonballs" that can reverse the wish and return him to adulthood.