based on D&D 5th Edition
Umberhulk
Huge  Monstrosity , Unaligned

Armor Class 18  (natural)
Hit Points 104  (11d12+33)
Speed 40 ft. , burrow 20 ft. , swim 20 ft.



STR DEX CON INT WIS CHA
20  (+5) 13  (+1) 16  (+3) 9  (-1) 10  (0) 10  (0)
Senses tremorsense,darkvision, passive Perception 10
Languages
Challenge 5  (0 XP)
Confusing Gaze. When a creature starts its turn withing 30 ft it makes a DC 15 Charisma saving throw. On a failure the creature can't take reactions, roll dice on 1-4 on 1d8 or less creature does nothing, 5-6 on 1d8 creature moves in random direction full speed, 7-8 on 1d8 creature makes melee attack against random nearest creature in reach. Creatures can choose to fight blind or use blindsight to get advantage against the gaze..
Tunneler. Can burrow through solid rock at half its speed..
Actions
Multiattack. Makes one mandible and two claw attacks
Claw. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 9 (1d8+5) slashing damage.
Mandibles. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 14 (2d8+5) slashing damage.