Artic Behemoth

Siege Monster. This creature does double damage to buildings and structures.

False Appearance. This creature is indistinguishable from a normal glacier or iceberg when laying completely still.

Cold Aura. Any creature that starts it's turn within 10 ft. of the Artic Behemoth takes 3d6 [cold] damage.

Multi-Attack. The Artic Behemoth makes three attacks: two with it's Stomp and one with it's Frost Breath.

Stomp. The Artic Behemoth smashes two creatures with it's rocky feet. Melee Attack: +6 to hit, reach 5 ft., 1 target. Hit: 2 (3d10 + 7) [bludgeoning] damage.

Spearicle Crush. The Artic Behemoth body-slams the targets. Melee Attack: +8 to hit, reach 15 ft. [cube]. Hit: 4 (4d10 + 7) [bludgeoning] damage + 2 (3d8 + 6) [piercing] damage. Any Small or Tiny creature hit is knocked unconscious and automatically loses a saving throw. 

Spike Chain. The Artic Behemoth stomps it's feet, creating a chain of ice or stone spikes, jutting from the ground. Ranged Attack: +6 to hit, range 20 ft., 2 targets. Hit: 2 (4d12 + 5) [piercing] damage + 2(6d6 + 4) [cold] or [bludgeoning] damage, depending on the terrain.

Frost Breath. The Artic Behemoth exhales a stream of freezing air from it's mouth. Ranged Attack: DEX 18, range 25 ft. [cone]. Hit: 1 (4d12 + 6), or half as much on a successful throw. Nearby water is now frozen solid, and is difficult terrain.

Ice Wall. This creature can create an ice wall 25 ft. long, 5 ft. thick, and 15 ft. high as a bonus action, but only after it has made a stomp attack.

Stomp. This creature can make two stomp attacks.

Spike Circlet. This creature can create a ring of spikes, ice or stone (depending on the terrain), to shoot out of the ground around it's foot. Can only be used after making a stomp attack. Any creature hit by these spikes are pushed back 10 ft., and the area becomes difficult terrain to any creature Medium size or smaller. Melee Attack: +5 to hit, 5 ft. radius. Hit: 2 (4d10 + 7) [piercing] damage + (6d6 + 6) [cold] or [bludgeoning] damage.

Shatter. If hit with [thunder] or [bludgeoning] damage equal to 1/4 of the Artic Behemoth's max HP, the Artic Behemoth can add an extra (2d8+2) to it's next melee attack at the cost of taking -3 from it's AC.

The Artic Behemoth gets three Legendary Actions. These actions replenish once they've been used.

Icebreaker (Costs 2 Actions). If the Artic Behemoth is standing on frozen water (such as a lake, or part of the ocean), it can choose to break the ice and submerge itself in the frigid water. Any creature within 15 ft. of the Behemoth are also dumped into the water and are stunned. Any attacks made against the Artic Behemoth will have disadvantage until it reemerges from the body of water.

Refreeze (Costs 1 Action). If the Artic Behemoth has reemerged after using it's Icebreaker action, it can use this only directly after reemerging. The Artic Behemoth refreezes it's ice shell with the water covering it, raising it's AC by +1 and restoring 15 HP.

Tail Swing (Costs 1 Bonus Action). The Artic Behemoth swings it's massive, rocky tail. Melee Attack: +10 to hit, reach 10 ft. Hit: 1 (2d6+8) [bludgeoning] damage.

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Mythic Action Name (Costs # Actions). Enter the description for your mythic action.