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 shirt, black pants, a right white (presumably gloved) claw/hand, and a blue left claw/hand. His insidious plan is to take over the island, whilst also destroying most of the island's buildings and landmarks in the process.

...yeah, not exactly the brightest of plans. It's kinda difficult to rule over a place when there's barely anything left to rule over, which The Brickster himself seems to realize during the bad ending of the game.