Dungeon Guardian

It spawns when a player enters the Dungeon below zero depth in a world where Skeletron has not been defeated.^[1] The Dungeon Guardian deals 9,999 damage per hit, instantly killing most players.^[1] It has 9,999 defense, so any attack normally deals only 1 damage, or 2 on a critical hit.^[1] Its Bestiary entry fills automatically once Skeletron is defeated.^[1]

The Dungeon Guardian moves at 41 mph and travels through all blocks.^[1] The Dungeon Guardian is a highly perilous foe that looks like Skeletron's head.^[1] Defeating a Dungeon Guardian gives the Bone Key pet summon, but demands thorough readiness.^[1] Dodge effects are bypassed by the Dungeon Guardian's damage.^[1]