The commander of a vast First Federation ship who tested Kirk with threats, before revealing his true, friendly nature.
Balok commands the Fesarius, a huge spherical ship of the First Federation that confronts the Enterprise after Kirk destroys a warning buoy. Through a fearsome image on the viewscreen, he threatens to destroy the ship, until Kirk bluffs by claiming the Enterprise carries corbomite, a substance that would destroy any attacker.
When Kirk answers a distress call from Balok's small vessel, he discovers that the threatening face was only a puppet. The real Balok, small and childlike, had been testing the humans' intentions, and he invites Lieutenant Bailey to stay with him. He was played by Clint Howard.