Ice sharks

As you walk over the slippery, icy floor of the cave, you feel the briefest tremor, and then - SNAP! Sharp teeth close around your ankle - an ice shark.

These sharks have conical noses and burrow through the solid perma-ice. They are very sensitive to tremors and hone in on animals walking on the surface. If players fail a DC15 Dexterity check, their teeth deal 1d10 damage.