Ice Walker. The ynricorsn is unaffected by difficult terrain imposed by ice, snow, and hail and cannot fall prone due to slippery surfaces. The ynircorsn can enter snow, ice, and permafrost terrains and end its turn there, but cannot cast spells or attack while inside the terrain. If the terrain surrounding a submerged ynircorsn is affected by fire damage, the ynircorsn is ejected and must make a DC 13 Dexterity saving throw or emerge prone as the medium it was travelling through loses its ice elemental energy.

Innate Spellcasting. The ynircorsn may cast the following spells. Its spellcasting ability is Wisdom (spell save DC 12, +4 to hit with spell attacks).
At will: Frostbite, Ray of Frost, Chromatic Orb (Cold)
1/day: Cone of Cold, Sleet Storm, Ice Storm

Multiattack. The ynircorsn makes two attacks: one with its stomp, and one with its bite.

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., 1 target. Hit: 2d4 + 4 piercing damage + 2d8 cold damage.

Stomp. Melee Weapon Attack: +7 to hit, reach 5 ft., 1 target. Hit: 1d10 + 4 bludgeoning damage + 2d4 cold damage. Target must succeed on a Strength saving throw (DC 15) or be knocked prone.

Freezing Northwind Tail. The ynircorsn wraps the magic of its blizzard tail around one creature within 10 feet. The target must make a Constitution saving throw (DC 15) or become paralyzed for 2 rounds as its muscles numb and lock. The ynircorsn must maintain concentration on this effect, and the affected creature may repeat the saving throw at the end of its turn. For casting purposes, this counts as a first level spell and can be affected by Counterspell.

Opportunity Attack. The ynircorsn makes one bite attack against a creature leaving its reach.