Cave Terror

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

Invoke Carnage. If the monsters HP fall on half of it maximum or less, it starts to walk on both its legs and arms, granting it 20 ft. additionaly on every moving speed it has. It gains 2 additional Legendary Actions. It also makes an fourth attack with its tail each turn. 

Multiattack. The monster makes two Claw attacks and one Bite attack.

Claw. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 48 (5d10 + 7) slashing damage.

Bite. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 56 (10d6 + 7) piercing damage.

Tail swing. Melee Weapon Attack: +12 to hit, reach 20 ft., one target. Hit: 42 (6d8 + 7) bludgeoning damage, and if the target is a creature, it must succeed on a DC 18 Strength saving throw or be knocked prone. 

 Climb. The monster can use the tentacles on it back to pierce into walls and roofs in order to climb almost any surface. 

Hunters Dash (3/Day). The monster can use the dash action with a bonus of 30 ft. walking speed. If this results in the monster to end up behind a creature it has Advantage on its next attack roll. After all three Actions have ben used the Creatures Exhaustions level increases by 1. 

Cunning Action. The monster can take a bonus action on each of its turns to take the Dash, Disengage, or Hide action. 

Oppurtunity Attack.  when a hostile creature that the monster can see moves out of its reach. It can make the opportunity attack to make one melee attack against the provoking creature.

The beast can take 4 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 beast regains spent legendary actions at the start of its turn.

Charge (Costs 2 Actions). The creature moves up to its speed without provoking opportunity attacks, then makes two Claw attacks.

Frightful Roar (Costs 2 Actions). The creature lets out a roar . Any creature in a radius of 200 ft. makes a DC 18 Charisma saving throw.  Each creature that fails the safe is frightened of the monster 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.