Thrym HoundHuge monstrosity, neutral evilArmor Class 17 (natural armor)Hit Points 175 (13d12 + 91)Sp

Thrym Hound
Huge monstrosity, neutral evil
Armor Class 17 (natural armor)
Hit Points 175 (13d12 + 91)
Speed 40 ft.
Str24,Dex12,Con25,Int4,Wis18,Cha15
Damage Resistancescold
Senses passive Perception 14
Languages Common, Draconic, Giant
Challenge 10 (5900 XP)
Keen Smell. The Thrym hound has advantage on Wisdom (Perception) checks that rely on smell.
Ice-Spiked Hide. A creature that touches the Thrym hound or hits it with a melee attack while within 5 feet of it takes 2 (1d4) cold damage.
Actions
Multiattack.The Thrym hound makes one bite attack and two claw attacks.
Bite.Melee Weapon Attack: +11 to hit, reach 10 ft., one target.Hit: 17 (3d6+7) piercing damage plus 3 (1d6) cold damage.
Claw.Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit:14 (2d6+7) slashing damage plus 3 (1d6) cold damage.
Frigid Stare (Recharge 5-6). The Thrym hound’s eyes project bitter cold in a 60 foot line, 10 feet wide. Each creature in that area must make a DC 17 Dexterity saving throw, taking 45 (13d6) cold damage on a failed save, or half as much damage on a successful one. A creature that fails its save also has its speed halved until the end of its next turn.

These predators of the frozen waste are said to be a gift from the frost giant god  Thrym. Whether true or not, Thrym hounds are commonly kept as pets and warbeasts by the frost giants; though, they are also commonly encountered in the wild, sometimes alone, sometimes in packs. They sit comfortably at the top of the food chain, fearing only white dragons. Requiring only one large meal a year, these creatures often spend much of their time in the ice caves they make their lairs in. They do not keep treasure themselves, but it can often be found in their lairs among the bones of their victims. Thrym hounds stand around 12 feet tall, are around 30 feet long, and weigh approximately 15 tons.

Originally from the Monster Manual V.