Pinkymod/Chaos Maw

The Chaos Maw is a Hardmode found within the. It remains completely stationary but summons a group of 4 invincible dissonant wisps once on screen, the wisps rapidly pursue the player and charge at them if they get close. All the wisps will disappear if the Choas Maw either dies or despawns.

Bestiary Entry
Giant, maw of abyssal sludge and flesh, mutated several dozen times. Far worse of an abomination than anything the Crimson and the Corruption have, at least to me. They breed immortal wisps out of the ectoplasmic energy in the Dungeon's air. Slaying them also puts an end to the wisps. An alternative and more mind-friendly option would be to simply avoid them when you can.