Ancient Dracolisk

Amphibious. The dracolisk can breath air and water.

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

Petrifying Gaze. If a creature starts its turn within 30 feet of the dracolisk and the two of them can see each other, the dracolisk can force the creature to make a DC 20 Constitution saving throw if the dracolisk isn't incapacitated. On a failed save, the creature magically begins to turn to stone and is restrained. It must repeat the saving throw at the end of its next turn. On a success, the effect ends. On a failure, the creature is petrified until freed by the greater restoration spell or other magic.

A creature that isn't surprised can avert its eyes to avoid the saving throw at the start of its turn. If it does so, it can't see the dracolisk until the start of its next turn, when it can avert its eyes again. If it looks at the dracoliak in the meantime, it must immediately make the save.

If the dracolisk sees its reflection within 30 feet of it in bright light, it mistakes itself for a rival and targets itself with its gaze.

Multiattack. The dracolisk can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 20 (2d12 + 7) piercing damage plus 4 (1d8) acid damage and 4 (1d8) poison damage.

Claw. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 14 (2d6 + 7) slashing damage.

Tail. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 16 (2d8 + 7) bludgeoning damage.

Frightful Presence. Each creature of the dracolisk's choice that is within 120 feet of the dracolisk and aware of it must succeed on a DC 16 Wisdom saving throw or 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's saving throw is successful or the effect ends for it, the creature is immune to the dracolisk's Frightful Presence for the next 24 hours.

Acid Breath (Recharge 5-6). The dracolisk exhales acid in a 15-foot line that is 5 feet wide. Each creature in that area must make a DC 20 Constitution saving throw, taking 58 (13d8) acid damage on a failed save, or half as much damage on a successful one.

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

Detect. The dracolisk makes a Wisdom (Perception) check.

Tail Attack. The dracolisk makes a tail attack.

Wing Attack (Costs 2 Actions). The dracolisk beats its wings. Each creature within 10 feet of the dracolisk must succeed on a DC 21 Dexterity saving throw or take 14 (2d6 + 7) bludgeoning damage and be knocked prone.The dracolisk can then fly up to half its flying speed.