Frost Worm
Gargantuan Monstrosity, UnalignedHabitat Arctic
Frost worms burrow through the snow, dirt, ice, and rock of Wildemount's Biting North. These enormous monstrosities eagerly consume any living creature they can wrap their jaws around.
A frost worm spends most of its time beneath the frozen ground, conserving energy while it waits for prey to pass overhead. Smart travelers can identify a frost worm's hunting grounds by looking for recently iced-over tunnels. When the worm senses vibrations above, it bursts forth through dirt, ice, and snow. Those who escape its initial assault must still contend with the worm's haunting trill—a hypnotizing call that stops creatures in their tracks to make easy prey.
AC 18 (natural armor)
HP 264 (16d20 + 96)
Speed 40 ft., burrow 30 ft.
STR
28 (+9)
Save +9
DEX
8 (-1)
Save -1
CON
22 (+6)
Save +12
INT
1 (-5)
Save -5
WIS
5 (-3)
Save +3
CHA
5 (-3)
Save -3
Saving Throws CON +12, WIS +3
Vulnerabilities Fire
Immunities Cold
Senses Blindsight 30 ft., Tremorsense 60 ft., Passive Perception 7
Languages —
CR 17
Traits
Freezing Body. A creature that touches the worm or hits it with a melee attack while within 5 feet of it takes 10 (3d6) Cold damage.
Death Burst. When the worm dies, it explodes in a burst of frigid energy. Each creature within 60 feet of it must make a DC 20 Dexterity Saving Throw, taking 28 (8d6) Cold damage on a failed save, or half as much damage on a successful one. Creatures inside the worm when it dies automatically fail this saving throw.
Tunneler. The worm can burrow through solid rock at half its burrow Speed and leaves a 10-foot-diameter tunnel in its wake.
Actions
Multiattack. The worm makes two Bite attacks, or it uses Trill and makes one Bite attack.
Bite. Melee Attack Roll: +15, reach 10 ft. 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 has the Blinded and Restrained conditions, 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 in a space within 10 feet of the worm and have the Prone condition.
Trill. The worm emits a haunting cry. Each creature within 60 feet of the worm that can hear it must succeed on a DC 20 Wisdom Saving Throw or have the Stunned condition for 1 minute. A creature can repeat the saving throw each time it takes damage and at the end of each of its turns, ending the effect on itself on a success. Once a creature successfully saves against this effect, or if the effect ends 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.