Ancient Aboleth of the Submerged Core

Amphibious. The aboleth can breathe air and water.

Eldritch Restoration. If destroyed, the aboleth gains a new body in 5d10 days, reviving with all its Hit Points in the Far Realm or another location chosen by the DM.

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

Mucus Cloud. While underwater, the aboleth is surrounded by mucus. Constitution Saving Throw: DC 14, each creature in a 5-foot Emanation originating from the aboleth at the end of the aboleth’s turn. Failure: The target is cursed. Until the curse ends, the target’s skin becomes slimy, the target can breathe air and water, and it can’t regain Hit Points unless it is underwater.

While the cursed creature is outside a body of water, the creature takes 6 (1d12) Acid damage at the end of every 10 minutes unless moisture is applied to its skin before those minutes have passed.

Probing Telepathy. If a creature the aboleth can see communicates telepathically with the aboleth, the aboleth learns the creature’s greatest desires.

Multiattack. The aboleth makes two Tentacle attacks and uses either Consume Memories or Dominate Mind if available.

Tentacle. Melee Attack Roll: +9, reach 15 ft. Hit: 12 (2d6 + 5) Bludgeoning damage. If the target is a Large or smaller creature, it has the Grappled condition (escape DC 14) from one of four tentacles.

Psychic Crush.  Ranged Spell Attack Roll: +10, range 90 ft., 1 target Hit: 32 (5d10 + 5) Psychic damage.

Enslave(2/Day). Wisdom Saving Throw: DC 18, one creature the aboleth can see within 30 feet. Failure: The target has the Charmed condition until the aboleth dies or is on a different plane of existence from the target. While Charmed, the target acts as an ally to the aboleth and is under its control while within 60 feet of it. In addition, the aboleth and the target can communicate telepathically with each other over any distance.

The target repeats the save whenever it takes damage as well as after every 24 hours it spends at least 1 mile away from the aboleth, ending the effect on itself on a success.

Legendary Action Uses: 3 . Immediately after another creature’s turn, the aboleth can expend a use to take one of the following actions. The aboleth regains all expended uses at the start of each of its turns.

Reel (2 Actions):  The Aboleth targets one creature it has enslaved or grappled. It pulls the creature up to 60 feet toward itself.

Disrupt Magic (3 Actions): | The Aboleth targets one creature. If the creature is maintaining a spell (like Water Breathing or Haste), it must succeed on a DC 18 Constitution saving throw or the spell ends.

Mind Fog (1 Action):  The Aboleth expels psychic ink. Creatures within a 20-foot radius sphere centered on the Aboleth must make a DC 18 Wisdom saving throw or be Blinded until the end of their next turn.