Ancients Awakened/Mire Soul

Mire Souls are post-Moon Lord Boss Servants summoned by when one of his fake heads is destroyed. They cannot be damaged and pass through blocks, attempting to damage the player. The defeat of Yamata no Orochi destroys all Mire Souls alive.

Trivia

 * Despite them sharing a similar AI to Shadowflame Apparitions, their sprites are similar to the dragon ghasts summoned by Ghastly Glaive.