Chaos Elemental

The Chaos Elemental is an enemy that spawns in the Cavern layer. This enemy is capable of teleporting, not unlike enemies such as the Fire Imp and Goblin Sorcerer, but at a much more rapid rate, and these teleportions will normally be aimed at getting in melee range of the player than staying away from him.

Depending on whether it's killed inside an Underground Hallow or Underground Corruption Soul of Light or Soul of Night can be dropped.