The Skeleton Ghoul

The skeleton ghoul is a bot in chapter 2-Attic. He spawns when you have the hammer and destroy the boxes and pick up the book. When the skeleton ghoul is active. Catasorus will be unactive and stunned on the floor. the ghoul skeleton will explode, presumably dying you use the syringe on the potion

How to obtain.
To obtain, you must get the true ending of The Attic chapter.