Frost worm

Frost worms are monstrosities native to Exandria's frigid regions. These gargantuan creatures are ambush predators, lurking beneath the snow waiting for the telltale vibrations of prey passing overhead.

Appearance
Frost worms are enormous worms with purple flesh and white scales. They have no eyes, instead relying on their blindsight and tremorsense to detect prey.

Abilities

 * Multiattack: The worm makes two bite attacks, or uses its Trill and makes one bite attack.
 * Bite: +15 to hit, reach 10 ft., one target. Hit: 22 (3d8 + 9) piercing damage plus 10 (3d6) cold damage. If the target is a Large or smaller creature, it must succeed on a DC 20 Dexterity saving throw or be swallowed by the worm. A swallowed creature is blinded and restrained, has total cover against attacks and other effects outside the worm, and takes 10 (3d6) acid damage and 10 (3d6) cold damage at the start of each of the worm’s turns. If the worm takes 30 damage or more on a single turn from a creature inside it, the worm must succeed on a DC 20 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of the worm.


 * Trill: The frost worm emits a haunting cry. Each creature within 60 feet of the worm that can hear it must succeed on a DC 20 Wisdom save or be stunned for one minute. A stunned creature can repeat the save if it takes damage, and at the end of its turn. Once a creature successfully saves or the effect expires for it, that creature is immune to the Trill of all frost worms for the next 24 hours. Frost worms are immune to this effect.

Vox Machina fought a purple worm and a frost worm in Brimscythe's former lair.

The Mighty Nein encountered a frost worm as they traversed the isle of Foren in Eiselcross with their guide, Dagen Underthorn. After everyone but Jester was stunned by the worm's Trill, Jester successfully Polymorphed it. The party then fled from the creature while it was helplessly left as a turtle, spinning on its back on a frozen-over lake.