Aboleth

An ancient, aquatic abomination with a serpentine body, slimy skin, and multiple tentacles around its mouth. It possesses powerful psionic abilities, a mucus that enslaves minds, and the ability to create illusions. Beware its intelligence, as it manipulates from the depths, seeking to dominate and control all it encounters.

Special Abilities

Amphibious

The aboleth can breathe air and water.

Mucous Cloud

While underwater, the aboleth is surrounded by transformative mucus. A creature that touches the aboleth or that hits it with a melee attack while within 5 ft. of it must make a DC 14 Constitution saving throw. On a failure, the creature is diseased for 1d4 hours. The diseased creature can breathe only underwater.

Probing Telepathy

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

Actions

• Multiattack: The aboleth makes three tentacle attacks.
• Tentacle: Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 12 (2d6 + 5) bludgeoning damage. If the target is a creature, it must succeed on a DC 14 Constitution saving throw or become diseased. The disease has no effect for 1 minute and can be removed by any magic that cures disease. After 1 minute, the diseased creature’s skin becomes translucent and slimy, the creature can’t regain hit points unless it is underwater, and the disease can be removed only by heal or another disease-curing spell of 6th level or higher. When the creature is outside a body of water, it takes 6 (1d12) acid damage every 10 minutes unless moisture is applied to the skin before 10 minutes have passed.
• Tail: Melee Weapon Attack: +9 to hit, reach 10 ft. one target. Hit: 15 (3d6 + 5) bludgeoning damage.
• Enslave: The aboleth targets one creature it can see within 30 ft. of it. The target must succeed on a DC 14 Wisdom saving throw or be magically charmed by the aboleth until the aboleth dies or until it is on a different plane of existence from the target. The charmed target is under the aboleth’s control and can’t take reactions, and the aboleth and the target can communicate telepathically with each other over any distance.
  Whenever the charmed target takes damage, the target can repeat the saving throw. On a success, the effect ends. No more than once every 24 hours, the target can also repeat the saving throw when it is at least 1 mile away from the aboleth.

Legendary Actions

• Detect: The aboleth makes a Wisdom (Perception) check.
• Tail Swipe: The aboleth makes one tail attack.
• Psychic Drain (Costs 2 Actions): One creature charmed by the aboleth takes 10 (3d6) psychic damage, and the aboleth regains hit points equal to the damage the creature takes.

Lair Actions

1. Hallucinatory Terrain:
   • The Aboleth bends the very fabric of reality within its lair. It chooses a point it can see within 60 feet. A 20-foot radius centered on that point is transformed to look, sound, and smell like another environment (deep ocean trench, otherworldly abyss, or a sunken city, for instance). The area becomes difficult terrain. This illusion lasts until the Aboleth uses this lair action again or until the Aboleth is defeated. Creatures in the area when the illusion appears must make an Intelligence (Investigation) check against the Aboleth’s Spell Save DC or believe it to be real.
2. Murky Waters:
   • The Aboleth causes the water in its lair to become thick and opaque. For the next round, the entire underwater section of its lair becomes heavily obscured, and creatures other than the Aboleth within that water are blinded.
3. Psychic Echos:
   • The Aboleth sends out a pulse of psychic energy. Every creature of the Aboleth’s choice within the lair must succeed on a Wisdom saving throw against the Aboleth’s Spell Save DC or be overwhelmed by fragmented memories and thoughts, becoming incapacitated until the end of their next turn.
4. Whirlpool:
   • The Aboleth stirs the water in its lair with its powerful mind, creating a whirlpool at a location it chooses within 60 feet. This whirlpool has a radius of 10 feet and moves up to 30 feet in a direction of the Aboleth’s choice during each of its turns. Creatures caught in the whirlpool must succeed on a Strength saving throw against the Aboleth’s Spell Save DC or be pulled 10 feet toward the center and take bludgeoning damage.
5. Ancient Binding:
   • The Aboleth recalls ancient pacts and bindings it has forged with entities from the depths. It summons a water elemental to a location it chooses within 60 feet. The elemental is friendly to the Aboleth and follows its commands, acting on the same initiative as the Aboleth. The elemental disappears when it drops to 0 hit points or after 1 hour.

The Aboleth can use one of its lair actions at the end of another creature’s turn, and it can’t use the same lair action two rounds in a row.

Proficiencies

• Saving Throw: CON +6
• Saving Throw: INT +8
• Saving Throw: WIS +6
• Skill: History +12
• Skill: Perception +10