Aurumvorax

A massive, terrifying monster resembling an 8-legged wolverine. It is very dangerous, with jagged claws and teeth that can go through metal.
Aurumvorax are very difficult to kill. While many animals may be disabled after they're injured and bleeding out, Aurumvorax can fight even while on their death bed. (Mechanically, they don't go down when HP drop to zero and must be damaged several more times after that).
They have been known to live in hilly areas in large holes.