(Most of the stats are completely ripped from what I found online, but the actions I tacked on. I'm garbage at making my own stats. This is for a boss fight of 4 characters, a level 11, level two lvl 10s and a level 5, it's a long story as to why the levels are like that but that's where they're at)

Please let me know what you think.

Wendigo Alpha

AC 16

HP 150 (20d8 60)

Speed 40 ft.

STR DEX CON INT WIS CHA

21 ( 5) 18 ( 4) 16 ( 3) 11 ( 0) 16 ( 3) 12 ( 1)

Skills Athletics 9, Perception 7, Stealth 8, Survival 7

Damage Vulnerabilities: Fire

Damage Resistances bludgeoning, piercing, and slashing from nonmagical attacks

Damage Immunities cold

Condition Immunities exhaustion

Senses darkvision 120 ft., passive Perception 17

Aura of Starvation. A creature that starts its turn within 10 feet of the wendigo must succeed on a DC 15 Constitution saving throw or be paralyzed by gnawing cold and crippling hunger for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the wendigo’s Aura of Starvation for the next 24 hours.

Cannibalistic Regeneration: Each time the Wendigo successfully deals damage it regains half of the damage it dealt. If the wendigo takes fire damage this effect does not apply

Magic Resistance. The wendigo has advantage on saving throws against spells and other magical effects.

Multiattack. The wendigo makes three attacks: two with its icy claw and one with its bite. Alternatively, it uses its Frozen Spittle twice.

Icy Claw. Melee Weapon Attack: 9 to hit, reach 5 ft., one target. Hit: 12 (2d6 5) slashing damage and 14 (4d6) cold damage.

Bite. Melee Weapon Attack: 9 to hit, reach 5 ft., one target. Hit: 14 (2d8 5) piercing damage.

Frozen Spittle. Ranged Spell Attack: 7 to hit, range 100 ft., one target. Hit: 28 (8d6) cold damage, and the target must succeed on a DC 16 Dexterity saving throw or be restrained until the end of its next turn.

Actions

Inhuman Mobility: As a bonus action the wendigo can disengage and move 20 feet in any direction without taking an opportunity attack as long as they end their turn within 5 feet of an enemy or other wendigo

Mimicking Screech (upon taking damage the first time, or again after a critical hit): The Wendigo can let out a horrifying screech, using the voice of an enemy in unbearable pain. All enemies within earshot must make a DC 15 Wisdom Save or be frightened for 1 minute.

Frozen Frenzy (3rd round or below 30hp): The Wendigo drives itself and nearby allies into a riotous frenzy, allowing all of them to immediately take another attack action and giving advantage to all attacks from then on.