Brain of Cthulu

The  is a boss that spawnseither from breaking three Pulsating Hearts found just beyond the ends of the branches in The Crimson. It is a large brain that moves around slowly, but can fade and reappear elsewhere similar to teleporting. Upon spawning, it spawns several small orblike enemies that follow it around and occasionally launch towards the player.

Defeating this boss is not as straightforward as pre-1.2 bosses, as the brain itself is invulnerable until the orblike enemies have all been killed. Once they are killed, a cry similar to the Eye of Cthulhu's spawning cry will be heard, and the brain may be damaged.