King Kai's planet (界王界, Kaiōkai) is a planet located in the Other World. It is home to King Kai, ruler of the North Galaxy, as well as to King Kai's pets: Bubbles and Gregory. Even though the planet is relatively small, it has gravity that is 10 times that of Earth's, allowing for more intense training (clearly seen through Goku's struggle to even stand up). In addition, the planet carries apple trees, of which the apples in question, when dropped, would burrow down into the ground.