Peat Mammoth

Slow Burn. When the peat mammoth takes fire damage, it catches fire. If the peat mammoth starts its turn on fire, it takes 5 (1d10) fire damage. The mammoth's saturated body douses the fire at the end of the peat mammoth's turn. Creatures engulfed by the mammoth don't take fire damage from this effect. If the peat mammoth dies while it is on fire, it explodes in a burst of fire and flaming peat. Each creature within 15 feet of the peat mammoth must make a DC 17 Dexterity saving throw, taking 14 (4d6) fire damage on a failed save, or half as much damage on a successful one. If a creature is engulfed by the mammoth when it dies in this way, the creature has disadvantage on the saving throw.

Swamp Camouflage. The peat mammoth has advantage on Dexterity (Stealth) checks made to hide in swampy terrain.

Multiattack. The peat mammoth makes two slam attacks.

Slam. Melee Weapon Attack: +11 to hit, reach 10 ft., one creature. Hit: 20 (3d8 + 7) bludgeoning damage. If the peat mammoth is on fire, the target also takes 7 (2d6) fire damage.

Engulf. The peat mammoth moves up to its speed. While doing so, it can enter Large or smaller creatures' spaces. Whenever the mammoth enters a creature's space, the creature must make a DC 17 Dexterity saving throw. On a successful save, the creature can choose to be pushed 5 feet back or to the side of the mammoth. A creature that chooses not to be pushed suffers the consequences of a failed saving throw. On a failed save, the mammoth enters the creature's space, and the creature takes 22 (5d8) necrotic damage and is engulfed. The engulfed creature can't breathe, is restrained, and takes 22 (5d8) necrotic damage at the start of each of the mammoth's turns. When the mammoth moves, engulfed creatures move with it. An engulfed creature can try to escape by taking an action to make a DC 17 Strength check. On a success, the creature escapes and enters a space of its choice within 5 feet of the mammoth. The mammoth can engulf up to two Large or smaller creatures at a time.