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

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

Siege Monster. The Colossus deals double damage to objects and structures.

Ice Walk. The Colossus can walk along icy/snowy terrain without needing to make an ability check.

Frost Burn. Any melee attack that lands on the Colossus makes the attacker take 1d6 Cold Damage.

Multiattack. The Colossus is able to use it's frightening presence, then any combination of 2 melee attacks due to it's immense size. Or, in lieu it can use it's Cold Breath.

Bite. Melee Weapon Attack: +19 to hit, reach 10 ft., one target. Hit: 23 (3d12 + 10) piercing damage. If the target is a creature, it is grappled (escape DC 20). Until this grapple ends, the target is restrained, and the Colossus can’t bite another target.

Claw. Melee Weapon Attack: +19 to hit, reach 15ft., one target. Hit: 13 (2d8 + 10) slashing damage.

Tail. Melee Weapon Attack: +19 to hit, reach 20ft., one target. Hit: 14 (3d6 + 10) bludgeoning damage. If the target is a creature, it must succeed on a DC 20 Strength saving throw or be knocked prone.

Stomp. Melee Weapon Attack: Reach 50ft. Multiple targets. If a creature is within range, whether ally or enemy, it must roll a DC 20 Strength saving throw or be knocked prone and launched 20 foot away.

Frightful Presence. Each creature of the colossus's choice within 120 feet of it and aware of it must succeed on a DC 16 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the colossus's Frightful Presence for the next 24 hours.

The colossus 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 colossus regains spent legendary actions at the start of its turn.

Attack. The Colossus makes one claw attack or tail attack.
Bite Attack. The Colossus makes a bite attack.
Weakened Stomp. The Colossus makes a weaker version of the stomp attack, range, 25 foot.

The colossus makes one claw attack or tail attack.