Wubba Tubba, Troll Guardian

Legendary Resistance (3/day). If Wubba Tubba fails a saving throw, he can choose to succeed instead.

Magic Resistance. Wubba Tubba has advantage on saving throws against spells and other magical effects.

Regeneration. Wubba Tubba regains 20 hit points at the start of his turn. If he takes fire damage, he regains only 10 hit points at the start of his next turn. He dies only if he takes 30 or more fire damage while he has 0 hit points.

Multiattack. Wubba Tubba makes two Rend attacks and one Bite attack.

Rend. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 30 (4d10 + 8) slashing damage.

Bite. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 41 (6d10 + 8) piercing damage. If the target is a Large or smaller creature, it must succeed on a DC 18 Dexterity saving throw or be swallowed by Wubba Tubba. A swallowed creature has total cover against attacks and other effects outside Wubba Tubba, and it takes 14 (4d6) acid damage at the start of each of Wubba Tubba's turns. If Wubba Tubba takes 40 or more damage on a single turn from a creature inside him, he must succeed on a DC 16 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of him. If Wubba Tubba dies, a swallowed creature can escape from his corpse by using 20 feet of movement, exiting prone.

Wubba Tubba 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. Wubba Tubba regains spent legendary actions at the start of his turn.

Devour Flesh. Wubba Tubba accelerates his digestive process. Each creature swallowed by him takes 14 (4d6) acid damage and he regains hit points equal to half the damage dealt this way.

Hurl Scenery. Wubba Tubba throws a large rock, shrubbery, tree limb, or similar object at a point he can see within 300 feet of him. Each creature within 10 feet of that point must succeed on a DC 19 Dexterity saving throw, taking 33 (6d10) bludgeoning damage on a failed save, or half as much damage on a successful one.

Noxious Fumes (Costs 2 Actions). Wubba Tubba releases a cloud of nauseating fumes. Each creature within 30 feet of him must succeed on a DC 19 Constitution saving throw, taking 27 (5d10) poison damage on a failed save, or half as much damage on a successful one. A creature that fails its saving throw is also incapacitated until the end of its next turn.