Remorhaz

Massive, blue centipedes with neck hoods and red-hot spine spikes. Dwell in arctic climates.

AC 16, HP 47, ATK 3 bite +7 (2d6 + swallow), MV near (burrow), S 5, D 1, C 2, I -3, W 1, Ch -3, AL N, LV 10

Impervious. Immune to cold and fire.

Melt. Non-magical metal objects that touch the remorhaz melt on a d6 roll of 1-3.

Swallow. On a natural attack roll of 18-20, target is swallowed. Total darkness inside and 2d10 damage per round. Remorhaz regurgitates all swallowed if dealt at least 20 damage in one round to the inside of its gullet.