Christmas Demon

Ice Body. A creature that touches the Demon or hits it with a melee attack while within 5 feet of it takes 10 (3d6) cold damage.

Ice Chomp/Bite. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 8 (1d10 + 6) piercing damage plus 10 (2d6) cold damage. If the target is a creature, it is grappled (escape DC 15). Until this grapple ends, the target is restrained, and the Demon can't bite another target.

Swallow. The Demon makes one bite attack against a Medium or smaller creature it is grappling. If the attack hits, that creature takes the bite's damage and is swallowed, and the grapple ends. While swallowed, the creature is blinded and restrained, it has total cover against attacks and other effects outside the Demon, and it takes 6 (1d6) acid damage and 6 (2d6) cold damage at the start of each of the Demon's turns.

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