Cavern Troll

Senses Blindsight, Passive Perception 18

Keen Smell. The troll has advantage on Wisdom (Perception) checks that rely on smell.

Regeneration. The troll regains 20 hit points at the start of its turn. If the troll takes acid or fire damage, this trait doesn't function at the start of the troll's next turn. The troll dies only if it starts its turn with 0 hit points and is then dealt 10 points or more of fire or acid damage.

Damage Resistance Slashing, Piercing

Sunlight Petrification If exposed to direct sunlight, a cavern troll's movement immediately becomes halved and can't use reactions or Trample. The slowed value halves each time the cavern troll ends its turn in sunlight. If the cavern troll's actions fall below 5 in this way, they become petrified (no movement or actions) until it spends at least 1 minute in darkness. Spells that create magical sunlight cannot petrify a cavern troll.

Treorsense allows a monster to feel the vibrations through a solid surface caused by movement. It is an imprecise sense with a limited range (listed in the ability). Tremorsense functions only if the monster is on the same surface as the subject, and only if the subject is moving along (or burrowing through) the surface.

 Multiattack. The troll makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 7 (4d12 + 10) piercing damage.

Claw. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 11 (4d12 + 10) slashing damage.

Stomp Once at the end of each opponents turn The Cavern Troll may slam its foot onto the ground.  Every medium or smaller creature within 20 ft. must make a dexterity save DC 10 or be knocked prone.