Auðumbla

Charge. If the cow moves at least 20 feet straight toward a target and then hits it with a gore attack on the same turn, the target takes an extra 7 (2d4) piercing damage.

Multiattack. On its turn, the Auðumbla may attack twice using its Gore attack.

Gore. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 7 (1d12 + 6) piercing damage.

Primordial Stomp. Melee Weapon Attack: The Auðumbla rears up on its front hooves before rocketing its hind legs back down to the earth, throwing waves of primordial energy through the ground. All creatures within a 30ft radius of the Auðumbla must make a DC14 save or take 2d6 bludgeoning damage and be knocked prone. Creatures that succeed take half damage and remain standing. If the ground in that area is loose earth or stone, it becomes difficult terrain until cleared, with each 5-foot-diameter portion requiring at least 1 minute to clear by hand.