Ambushing Beserkr

Ambusher. In the beginning of an encounter, the ambushing berserkr can attack up to 3 surprised creatures that are within 15 feet of each other and the ambushing berserkr. It deals additional 4 (1d8) piercing damage to each creature it hits.
False Appearance. The ambushing berserkr buries itself into the snow. While it is motionless within the snow, it has advantage on its Dexterity (Stealth) check.
Rage. The ambushing berserkr has a +2 bonus to its damage rolls, and other benefits of the Rage feature (included in the attack).
Stunning Critical. If the ambushing berserkr scores a critical hit against a creature, the creature must succeed on a DC 15 Constitution saving throw or become stunned until the end of its next turn.
Svil Fortitude. The ambushing berserkr can hold its breath for twice as long and it is unaffected by cold weather, as well as the Black Winter’s Cold.
Wearing the Bear’s Skin. The ambushing berserkr gains +5 AC because of its Path of Berserkr (included in its AC)

Multiattack. The ambushing berserkr makes three melee attacks.

Battleaxe. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 9 (1d8 + 5) slashing damage.