Beotodus

Frostblight. Whenever a creature takes cold damage from one of the beotodus attacks or is within 5 feet of the beotodus when it moves for the first time on its turn, it must make a DC 17 Constitution saving throw or become afflicted with iceblight for 1 minute on a failed save. A creature that is resistant or immune to cold damage automatically succeeds on their saving throw.

Sensitive Ears. When a thunder spell is used within 60 feet of the beotodus while it is underground or partially submerged, it must make a DC 15 Constitution saving throw. On a failed save, the beotodus must immediately use its reaction to move toward the surface and fully emerged if it has the movement speed to do so. The beotodus automatically fails this saving throw if a sonic bomb is used within range of it.

Snow Armor (3/day). While in snowy terrain, the beotodus can use its bonus action to cover itself in a thick layer of snow. While covered in this snow, it gains a +2 bonus to its AC and it has resistance to bludgeoning damage. Additionally when a creature touches the beotodus or hits it with a melee attack while within 5 feet of it they must make a DC 17 Constitution saving throw or become afflicted with iceblight until the end of their next turn. Whenever the beotodus takes fire damage there is a 50% chance that the snow armor melts, reducing its AC bonus by 1. Once its bonus AC from this effect is reduced to 0, the effect ends.

Standing Leap. The beotodus' long jump is up to 30 feet and its high jump is up to 15 feet, with or without a running start.

Wade. The beotodus can partially submerge itself in snowy or icy terrain. While partially submerged, it has three-quarters cover (+5 bonus to AC and Dexterity saving throws) and can only use the following actions: horn attack, deadly Leap, and slip 'n' slide.

Multiattack. While above ground, the beotodus makes three attacks: one with its horn, one with its tail, and one with its hip check. It can replace any attack with the ice chunk attack. While partially submerged it uses its deadly leap and makes one attack with its horn.

Horn. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 14 (3d6 + 4) piercing damage.

Tail. Melee Weapon Attack. +8 to hit, reach 10 ft., one target. Hit: 17 (3d8 + 4) bludgeoning damage.

Hip Check. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 23 (3d12 + 4) bludgeoning damage.

Ice Chunk. Range Weapon Attack: +7 to hit, reach 20/40 ft., one target. Hit: 10 (2d6 + 3) bludgeoning damage plus 4 (1d8) cold damage.

Deadly Leap (Must be partially submerged). If the beotodus jumps at least 15 feet as part of its movement, it can then use this action to land partially submerged in a space that contains one or more other creatures. Each of those creatures must succeed on a DC 18 Strength or Dexterity saving throw (target's choice) taking 11 (2d6 + 4) bludgeoning damage plus 10 (3d6) cold damage and be knocked prone. On a successful save, the creature takes only half the damage, isn't knocked prone, and is pushed 5 feet out of the beotodus's space into an unoccupied space of the creature's choice. If no unoccupied space is within range, the creature instead falls prone in the beotodus' space.

Slip 'n' Slide (Recharge 5-6). The beotodus moves up to its speed, while spinning at an incredible speed, without provoking opportunity attacks. During this move it may move through other creatures. Any creatures the beotodus moves through must succeed on a DC 18 Dexterity saving throw, taking 17 (3d8 + 4) bludgeoning damage plus 13 (3d8) cold damage and knocked prone on a fail.

The beotodus can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The beotodus regains spent legendary actions at the start of its turn.

Detect. The beotodus makes a Wisdom (Perception) Check.

Attack (Costs 2 Actions). The beotodus makes one attack
with its tail while on land, or one attack with its horn
while partially submerged.