Keen Senses. The Xeno-Warren Abomination has advantage on Wisdom (Perception) checks that rely on smell or hearing.

Acidic Blood. When the Abomination takes damage from a melee attack, it sprays acid in a 10-foot radius. All creatures in the area must make a DC 16 Dexterity saving throw, taking 2d8 acid damage on a failed save or half as much on a successful one.

Alien Resilience. The Xeno-Warren Abomination has advantage on saving throws against being stunned or paralyzed.

Burrowing Hunter. The Abomination can burrow through nonmagical earth and stone at a speed of 20 feet. It leaves no tunnel behind unless it chooses to.

Cunning Predator. The Abomination has advantage on attack rolls against frightened or surprised creatures.

Alien Mind. The Xeno-Warren Abomination’s mind is so alien that any creature attempting to read its thoughts or communicate telepathically with it must succeed on a DC 18 Intelligence saving throw or take 4d6 psychic damage and be stunned until the end of their next turn.

Multiattack. The Xeno-Warren Abomination makes three attacks: one with its bite and two with its claws.

• Bite. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 18 (2d12 + 4) piercing damage, and the target must succeed on a DC 16 Constitution saving throw or be poisoned for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

• Claw. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 14 (2d8 + 4) slashing damage.

• Tail Strike. Melee Weapon Attack: +8 to hit, reach 15 ft., one target. Hit: 20 (3d10 + 4) piercing damage, and the target must make a DC 16 Strength saving throw or be knocked prone.

• Acidic Spit (Recharge 5-6). The Abomination spits acid in a 30-foot line that is 5 feet wide. Each creature in that line must make a DC 16 Dexterity saving throw, taking 35 (10d6) acid damage on a failed save, or half as much on a successful one.

Frightening Roar (1/Day). The Xeno-Warren Abomination emits a terrifying roar. Each creature of the Abomination's choice within 60 feet of it that can hear it must succeed on a DC 16 Wisdom saving throw or be frightened for 1 minute. A frightened target can repeat the saving throw at the end of each of its turns, with disadvantage if the Abomination is within line of sight, ending the effect on itself on a success.

1. Skittering Pounce. The Abomination moves up to its speed toward a creature it can see. If it ends its movement within 5 feet of that creature, it can make a claw attack as part of this bonus action.
2. Burrow Dive. The Abomination can burrow up to 10 feet into the ground, becoming heavily obscured until it emerges. It can emerge at the start of its next turn in a space within 30 feet.

3. Predator’s Instincts. The Abomination gains advantage on its next attack roll against a creature that is frightened or surprised.

Xeno Reflexes. When a creature the Abomination can see targets it with an attack, it can use its reaction to move up to 20 feet without provoking opportunity attacks.

The Xeno-Warren Abomination can take 2 legendary actions, choosing from the options below. Only one legendary action can be used at a time, and it can only be taken at the end of another creature's turn. The Abomination regains spent legendary actions at the start of its turn.

1. Leap Attack. The Abomination leaps up to 20 feet in any direction without provoking opportunity attacks and makes a claw attack against one target it lands next to.

2. Chittering Whisper. The Abomination emits an unsettling chittering sound. Each creature within 30 feet that can hear it must succeed on a DC 16 Wisdom saving throw or have disadvantage on their next attack roll or saving throw until the end of their next turn.

3. Tail Sweep (Costs 2 Actions). The Abomination sweeps its tail in a wide arc. Each creature within 10 feet of the Abomination must succeed on a DC 16 Dexterity saving throw or take 14 (2d8 + 4) bludgeoning damage and be knocked prone.