Frost-Worm

The Frost Worm is an Enchanted creature spawned by the Frostmarch.
It is a large Burrowing Worm covered in armored plates, presumably Frostcrag Ice, making it impenitrable to anything short of Frostbane. It uses primaly destruction based frost magic and Agility to combat anything that enters the Glacier.
Reyenirus Battlehorn faced one of these while Mere feet away from the Spire.