The Necronaut from 3.5e of the Monster Manual III book

Gargantuan undead, Chaotic Evil

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Armor Class: 20 (natural armor)

Hit Points: 304 (30d12+96)

Speed: 50 ft

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STR: 24 (+7)

CON: 20 (+5)

DEX: 8 (-1)

INT: 7 (-2)

WIS: 14 (+2)

CHA: 16 (+3)

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Saving Throws STR: +14, CON: +10, WIS: +12

CHA: +14, STR: +20

Damage resistances: Cold, Necrotic

Damage immunities: Poison; Bludgeoning, Piercing, and Slashing from nonmagical attacks.

Condition immunities: Blinded, Charmed, Deafened, Exhaustion, Frightened, Grappled, Paralyzed, Poisoned, Prone, Restrained, Sleep, Stunned

Senses: Blindsight 120 ft.

Languages: Infernal, Abyssal; Telepathy

Challenge: 14

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Cleave. If the target is within 10 feet of another creature, the slam attack hits each creature.

Trample. If the Necronaut moves at least 30 feet toward a creature, the target must succeed on a DC 20 Strength saving throw or be knocked prone. Creatures who are trampled take 30(10d6) bludgeoning damage.

Assimilate Corpse. The Necronaut can, as an action, add the corpse of a creature to its body. Once the corpse is added, the Necronaut begins assimilating it. This process takes one round to run its course heals some damage to the Necronaut. Ases on the size of the corpse: Small or smaller, 10 points healed; Medium, 30 points; Large, 60 points; Huge, 100 points; Gargantuan, 150 points; or Colossal, 210 points. Once a creature is fully assimilated, it cannot be raised from the dead. Before a creature is assimilated, an ally can pull it free with a DC 20 strength check.

Necromantic Effects. Necronauts are affected differently by some spells. Because each one is comprised of bones and corpses, spells that create undead deal 1d4 points of damage per caster level to a Necronaut.

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Multiattack. Can use Slam 4 times.

Slam. Melee Weapon Attack: +12 to hit, reach 20ft., one target. Hit: (4d6+7) bludgeoning damage. The creature must make a strength saving throw (DC 16) or be thrown 10ft. and be knocked prone.

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A towering shape seemingly built from bones and corpses, this creature rolls and lurches across the ground, searching around itself with four massive, angular arms.

The Necronaut is an undead monstrosity that abhors life. It communicates grudgingly with constructs and other undead, from whom others have learned what little is known about these macabre creatures. Necronauts are created by demons that on plains of bones in the abyss and then sent forth to the material plane to kill, and to grow by adding bones and corpses to their hulking forms. Individual Necronauts vary in shape but average about 20 feet tall, 20 feet wide, and 30-40 feet long; each one weighs some 50 tons.