Huge Undead, neutral evil
Armor Class 14 (natural armor)
Hit Points 126 (11d12+55)
Speed walk +20
Challenge 8
Saving Throws dex +0, wis +5
Skills perception +2
Damage Resistances nonmagic B/P/S attacks
Damage Immunities necrotic, poison
Condition Immunities blinded, poisoned
Senses blindsight 120', passive Perception 15
Languages understands Common and Darakhul but can't speak
Siege Monster. Double damage to objects/structures.
Turn Resistance. Advantage: saves vs. turn undead effects.
Undead Nature. Doesn't require air food drink or sleep.
Multiattack. Two Trample attacks.
Trample. Melee Weapon Attack: +8 to hit, 5 ft., one target, 21 (3d10+5) bludgeoning damage.
Ballista Shot. Chooses up to two points it can see within 120' of it. The thunderer can't choose a point within 10 ft. of it. Each creature within 5 ft. of a point must make a DC 15 Con save taking 14 (4d6) necrotic on a failed save and half damage if made. If a creature is within 5 ft. of both points it has disadvantage on the save but it takes damage from only one effect not both.
Concentrated Shot (Recharge 5-6). Picks a point it can see within 120' of it. Each creature within 20' of that point must make a DC 15 Con save. On a failure a creature takes 35 (10d6) necrotic and suffers one level of exhaustion. On a success a creature takes half the damage and doesn't suffer a level of exhaustion.
Source: Tome of Beasts 3 · OGL/Open