Creepers are eyeball-like 敌怪 that are spawned in groups of 20 to 30 as part of the 克苏鲁之脑 Boss fight. They orbit the Brain of Cthulhu during the first phase, following the boss even as it teleports, acting as a shield of sorts. Once all Creepers are defeated, the Brain of Cthulhu continues the fight in its second phase, and the Creepers never appear again during the battle. They are immune to the 困惑 减益 and drop 心s only when the player isn't at maximum 生命值 (this doesn't affect other drops). In extremely rare cases, creepers may not appear at all, making the Brain of Cthulhu invulnerable.