Water Drake

Elemental Nature. The drake is not affected by environments characterized by extreme heat or extreme cold.

Legendary Resistance (3/Day). If the drake fails a saving throw, it can choose to succeed instead.

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

Mind Sense. The drake cannot be Surprised by a creature that it can sense using its telepathy, and its thoughts cannot be read using magic. The drake cannot be the target of a Possession ability.

Multiattack. The water drake makes one Bite attack and two Claw attacks, and can replace one attack with a use of Icy Fury if available.

Bite. Melee Weapon Attack: +15 to hit, reach 5 ft., one target. Hit: 14 (1d10 + 9) Piercing damage, and if the target is Large or smaller, the target must succeed a DC 24 Strength (Athletics) check or be Grappled (escape DC 24). The drake can only have one creature Grappled at a time.

Claw. Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 14 (2d4 + 9) Slashing damage.

Icy Fury (1/Day). Dexterity Saving Throw: DC 24, all creatures in a 15-foot-radius sphere within 60 feet from the air drake. Failure: A creature takes 16 (3d10) Cold damage and is Restrained. Success: The creature takes half damage and is not Restrained.

Spellcasting (Psionics). The drake casts the following spells without components, using Charisma as its spellcasting ability (spell save DC 18):

 At Will: Mage Hand (the hand is Invisible), Misty Step

1/Day: Clairvoyance, Banishment, Invisibility, Project Image

Legendary Action Uses: 3. Immediately after another creature's turn , the drake can expend a use to take one of the following actions. The drake regains all expended uses at the start of each its turns.

Tail. Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 16 (2d6 + 9) Bludgeoning damage, and the target must succeed a DC 25 Constitution saving throw or be Stunned until the start of the drake's next turn.

Swallow. The drake chooses one creature that it has Grappled and swallows it. While swallowed, the creature is Blinded and Restrained, it has total cover against attacks and other effects outside the drake, and it takes 17 (5d6) Acid damage at the start of each of the drake's turns. The drake can only have one creature Swallowed at a time, and the drake can't take this action again until the start of its next turn.

If the drake takes 20 damage or more on a single turn from a creature inside it, the drake must succeed on a DC 15 Constitution saving throw at the end of that turn or regurgitate the swallowed creature, which falls Prone in a space within 10 feet of the drake. If the drake dies, a swallowed creature is no longer Restrained by it and can escape from the corpse by using 10 feet of movement, exiting Prone.

Misty Step. The drake casts Misty Step using the same ability as Spellcasting.