Goo Skulls

The Goo Skulls are a specie of skeleton that reside in The Vault of Bones. They are seen crawling on walls and can eject streams of adhesive "goo" originating from an organ in the rib cage from their mouths'. They use this stream to both catch and encase their prey like spiders. They live in cave system made out of this same goo.

Appearance
The body of a goo skull is a typical humanoid skeleton, but the actual skulls differ between individual goo skulls. They have a pair of pale, green eyes as well as a tongue. Filling the rib cage, there is a green organ that contains their "goo". On each goo skull, there is a kitchen utensil strapped to either it's head or muzzle. The boss goo skull, however, has chainsaws strapped all over itself, include the head.

Trivia

 * There goo appears to be highly flammable