Brickster

The Brickster is a classic mustache-twirling cartoon villain, and the scourge of LEGO Island. He's also the only occupant of the one jail cell on the island, located right next to the police station. His name (obviously) is a pun on the terms "trickster" and "brick". As for his appearance, he's the same height as every other LEGO person on the island. He sports what the manual calls a "bad guy mask", a black-and-white striped prison uniform shirt, black pants, one white (presumably gloved) claw/hand, and a blue left claw/hand.