Acid Blood. When the Xenomorph is hit by an attack that deals piercing or slashing damage, one creature within 5 feet of the Xenomorph must make a DC 15 Dexterity saving throw, taking 7 (2d6) acid damage. on a failed save, or half as much damage on a successful one. The Xenomorph can choose which creature is targeted by its acid, preferring to target the creature that hit it, within range.

Legendary Resistance (3/Day). If the Xenomorph fails a saving throw, it can choose to succeed instead.

Claw. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 9 (1d6 + 6) slashing damage. 

Double Bite. Melee Weapon Attack: +10 to hit, range 5 ft., one target. Hit: 9 (1d6 + 6) piercing damage plus 3 (1d6) bludgeoning damage. The Xenomorph has advantage on this attack roll if targeting a creature it has grappled.

Tail. Melee Weapon Attack: +10 to hit, range 10ft., one target. Hit: 15 (2d8 + 6) piercing damage.

The Xenomorph can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time, and only at the end of another creature's turn. The Xenomorph regains all spent legendary actions at the start of its turn.

Claw. The Xenomorph makes a claw attack.

Grab. The Xenomorph can attempt to grab a creature.

Scurry. The Xenomorph Disengages and moves up to its speed.