The planet is introduced in the Babidi Saga, when Goku, Vegeta, and Gohan are in Babidi's spaceship. When the three Z Fighters are at Stage One, they use Rock-Paper-Scissors to decide who goes first. Vegeta is the victor, and gets ready to fight Pui Pui. With Vegeta dominating the battle, Babidi transports Pui Pui to his home planet, so that he will have an advantage while fighting Vegeta. However, Vegeta, due to his previous training under 450 times the gravity of Earth, and due to his upbringing on Planet Vegeta which has the same level of gravity, is unaffected by the change in gravity and effortlessly slaughters Pui Pui in minutes using his Double Galick Cannon on him. The planet is never mentioned again.
Video Game Appearances
Planet Zoon is a playable battle stage in Dragon Ball Z: Shin Butōden. When fighting in Babidi's spaceship in Dragon Ball Z: Supersonic Warriors 2, the fighters are sometimes teleported to a planet that looks similar to Planet Zoon.
It is mentioned in Dragon Ball Z: Buu's Fury, but does not appear.