Hagfish: The Jawless "Slime Eel"
This eel-like creature is an anatomical anomaly. It's the only known living animal that lacks a backbone and jaw but still has a skull. Hagfish secrete a goo when attacked that expands when combined with water. The predator is then choked by the expanded goo.
from Epic Wildlife
Key Facts In This Video
The hagfish is the only known living animal with a skull but no spine. (0:20)
The hagfish does not have a jaw, but rather tooth-like projections. (0:42)
The hagfish secretes a micro-fiber slime that expands when combined with water and chokes its attackers. (0:59)