Writhing Remains

The Writhing Remains is a pet item that can be dropped by Eater of Worlds in Master mode at a chance. It summons a pet Eater of Worms. It acts similar to The Deactivated Probe, which is the Master mode pet of The Destroyer.

Trivia
The buff tooltip "May ruin several backyards" could possibly be a reference to worms digging many holes in backyards.