Undead Frost Giant

Cold to the Bone: Each creature that starts its turn with 15 ft of the Giant must make a DC 13 Constitution Saving Throw or take 11 (3d6) Cold Damage. 

Multiattack. The giant makes three attacks using Frost Sword or Frozen Grasp in any combination, and may replace one of the attacks with Glacial Slam if its available. 

Frost Sword. Melee Attack Roll: DR 22 (target rolls1d20 + AC - 10), reach 15 ft line from the giant, any target in the line, 19 (2d12 + 6), plus 11 (2d10) Cold damage.

Frozen Grasp: Melee Attack Roll: DR 22, reach 15f, one target; 16 (3d10) cold damage. The target is Grappled. The creature may break the grapple at the beginning of their turn - DC 16 Strength Saving Throw.

Glacial Slam (Recharge 5-6): Each creature with a 15 ft of the Giant makes a DC 16 Dexterity Saving Throw. Fail: 28 (8d6) Cold damage and loses half of their movement speed until the end of their next turn. Success: Half damage, and no speed reduction. 

War Cry (Recharge 4–6); The giant or one creature of its choice that can see or hear it gains 32 (4d10 + 5) Temporary Hit Points and has Advantage on attack rolls until the start of the giant’s next turn.

The Undead Frost Giant has 3 legendary charges. Only one may be used per turn. 

Ice Armor: The Giant coats itself in ice reducing the damage it takes by 50% on one attack. This must be announced before the damage is dealt.

Body Shield: If the Giant has a creature grappled, it may use that creature as a shield. The creature receives 50% of the damage and the Giant receives none. However, the grappled creature may its reaction to break free, with advantage  - DC 16 Strength saving throw.

Frozen Grasp: The Giant makes a DC 12 Wisdom Saving Throw. Success: The Giant can choose which creature to attack with Frozen Grasp. Fail: Choose a creature at random.