Tarrowmaw, the Glacial Hunger

Traits

• Legendary Resistance (3/Day). If the creature fails a saving throw, it can choose to succeed instead.
• Magic Resistance. The creature has advantage on saving throws against spells and other magical effects.
• Aura of Absolute Cold. At the start of each of Tarrowmaw's turns, each creature within 20 feet of it takes 11 (2d10) cold damage, and nonmagical flames within that area are extinguished. Water within 20 feet that isn't being worn or carried freezes solid.
• Siege Monster. Tarrowmaw deals double damage to objects and structures.

Innate Spellcasting

Their spellcasting ability is Charisma (spell save DC 20, +13 to hit with spell attacks).

Actions

• Avalanche Slam. Melee Weapon Attack: +16 to hit, reach 20 ft., one target. Hit: 35 (4d12 + 9) bludgeoning damage plus 13 (3d8) cold damage. If the target is a creature, it must succeed on a DC 24 Strength saving throw or be knocked prone and pushed up to 15 feet away. Difficult terrain of jagged ice fills the target's former space until the end of Tarrowmaw's next turn.
• Devouring Bite. Melee Weapon Attack: +16 to hit, reach 10 ft., one target. Hit: 36 (5d10 + 9) piercing damage plus 9 (2d8) cold damage. The target is grappled (escape DC 22) if it is a Huge or smaller creature. Until this grapple ends, the target is restrained, and Tarrowmaw can't bite another target.
• Rimebreath. Tarrowmaw exhales a roaring gale of glacial wind in a 90-foot cone. Each creature in the area takes 72 (16d8) cold damage. Each creature in that area makes a DC 24 Constitution saving throw, taking the cold damage on a failed save, or half as much on a success. A creature that fails is also restrained by encasing rime until the end of its next turn.

Bonus Actions

• Glacial Stride. Tarrowmaw moves up to half its speed. This movement ignores difficult terrain made of ice, snow, or rubble, and any creature whose space it enters or leaves must succeed on a DC 24 Strength saving throw or be knocked prone.

Reactions

• Shatterfrost Riposte. Brittle ice erupts from Tarrowmaw's wound. The attacker takes 18 (4d8) cold damage and must succeed on a DC 24 Constitution saving throw or have its speed reduced to 0 until the end of its next turn.

Legendary Actions

Tarrowmaw, the Glacial Hunger can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time, and only at the end of another creature's turn. Tarrowmaw regains spent legendary actions at the start of their turn.

• Avalanche Slam.
• Rimebreath (Costs 2 Actions).