Adult Ice Dragon

Iceblood

Whenever a creature hits the dragon with a melee attack while within 5 feet of it, the attacker must succeed on a DC 20 Constitution saving throw or have its speed reduced by 10 feet until the end of its next turn.

Snow Camouflage

The dragon has advantage on Dexterity (Stealth) checks made in snowy or icy terrain.

Multiattack

The dragon makes three attacks: one with its Bite and two with its Claws.

Bite

Melee Weapon Attack: +14 to hit, reach 15 ft., one target.
Hit: 21 (3d8 + 8) piercing damage plus 13 (3d8) cold damage.

Claw

Melee Weapon Attack: +14 to hit, reach 10 ft., one target.
Hit: 17 (2d8 + 8) slashing damage plus 7 (2d6) cold damage.

Tail Smash

Melee Weapon Attack: +14 to hit, reach 20 ft., one target.
Hit: 19 (2d10 + 8) bludgeoning damage plus 4 (1d8) cold damage.

The target must succeed on a DC 22 Strength saving throw or fall prone.

Frost Breath (Recharge 5–6)

The dragon exhales a blizzard of freezing wind in a 90-foot cone.

Each creature in the area must make a DC 21 Constitution saving throw, taking 67 (15d8) cold damage on a failed save, or half as much on a successful save.

A creature that fails the save has its speed reduced to 0 until the end of its next turn.

Glacial Cataclysm (Recharge 6)

The dragon causes jagged glaciers to erupt from the ground at a point it can see within 120 feet.

Creatures in a 30-foot-radius, 40-foot-high cylinder must make a DC 21 Dexterity saving throw.

On a failed save, a creature takes 36 (8d8) piercing damage plus 27 (6d8) cold damage and becomes restrained in magical ice for 1 minute. On a successful save, the creature takes half damage and isn’t restrained.

A restrained creature can use an action to make a DC 21 Strength check, freeing itself on a success.

Frozen Reprisal

When the dragon takes damage from a creature within 60 feet, it launches razor-sharp ice shards.

The attacker must make a DC 21 Dexterity saving throw, taking 18 4d8 piercing and cold damage on a failed save, or half as much on a success.

Legendary Action Uses: 3 (4 in Lair). Immediately after another creature's turn , the dragon can expend a use to take one of the following actions. The dragon regains all expended uses at the start of each its turns.

Cloud of Insects. Dexterity Saving Throw: DC 17, one creature the dragon can see within 120 feet. Failure: 22 (4d10) Poison damage, and the target has Disadvantage on saving throws to maintain Concentration until the end of its next turn. Failure or Success: The dragon can’t take this action again until the start of its next turn.

Frightful Presence. The dragon uses Spellcasting to cast Fear. The dragon can’t take this action again until the start of its next turn.

Pounce. The dragon can move up to half its Speed, and it makes one Rend attack.