King Moai is the ruthless king of Planet Arlia. He appeared only in Episode 7 of Dragonball Z, Trouble on Arlia (and its counterpart in the redub).
Moai imprisoned all the good Arlians and stole Atla's wife, Queen Lemlia, from him. He also held battles between his guards for championship. Any losers who survived, such as Greger, were thrown into The Pit and eaten by a feared monster, Yetti.
One day, Vegeta and Nappa arrived on Arlia. They allowed themselves to be taken prisoner before they escaped and confronted the king. Moai sent his current champion, Lesoy, after them, but Vegeta killed him. Nappa made quick work of Moai's guards, so he sent Yetti after them. Nappa easily destroyed the beast, and as Moai tried to run, Vegeta shot a rock through his chest, killing him.