Aberrant Anatomy. The Abomination’s body is twisted and warped beyond recognition, making it resistant to normal weapons and capable of withstanding terrible punishment. The first time the Abomination would be reduced to 0 hit points, it instead regains 50 hit points and its flesh violently contorts, causing all creatures within 10 feet of it to make a DC 15 Dexterity saving throw or take 13 (3d8) necrotic damage. After this transformation, its attacks deal an additional 1d8 necrotic damage.

Gaze of the Unforgotten. As a bonus action, the Abomination can focus its malevolent gaze on a single creature it can see within 30 feet. The target must succeed on a DC 14 Wisdom saving throw or be filled with visions of madness and despair, causing it to become Frightened 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. If a creature succeeds on the saving throw or the effect ends, it is immune to the Abomination’s Gaze of the Unforgotten for the next 24 hours.

Malformed Regeneration. The Abomination regains 10 hit points at the start of its turn. If the Abomination takes radiant damage or damage from holy water, this trait doesn’t function at the start of its next turn. The Abomination dies only if it starts its turn with 0 hit points and doesn’t regenerate.

Unholy Resilience. The Abomination has advantage on saving throws against spells and other magical effects.

Multiattack. The Abomination makes two Claw attacks.

Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 15 (2d8 + 4) slashing damage. If the target is a creature, it must succeed on a DC 15 Constitution saving throw or be afflicted with a festering curse, causing it to take 5 (1d10) necrotic damage at the start of each of its turns. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Horrific Screech (Recharge 5-6). The Abomination emits a bone-chilling scream that warps reality around it. Each creature within 30 feet that can hear it must succeed on a DC 15 Constitution saving throw or take 22 (4d10) necrotic damage and become stunned until the end of their next turn. On a successful save, creatures take half damage and are not stunned.

Twist of Flesh. When the Abomination is hit by a melee attack, it can use its reaction to twist its body grotesquely. The attacker must succeed on a DC 15 Dexterity saving throw or become grappled (escape DC 15) by the Abomination’s distended, rubbery limbs. While grappled in this way, the creature is restrained.