Silly lil guy.

DESCRIPTION: The Bone Ball is an enemy encountered in The Nameless City. It makes its first appearance in E3M4: Crypt of the Flesh and appears several times afterward, notably in E3M7: Homecoming.

APPEARANCE: Bone Balls appear as a hard, fleshy/bony sphere with several spikes sticking out of it. It is covered in red orifices that it uses as a means of attack and is capable of levitation. It has no discernible eyes or facial features.

(Thank you, DUSK wiki.)