AC 18 (natural armor)
HP 210 (20d10 + 100; bloodied 105)
Speed 10 ft., swim 40 ft.
Proficiency +5; Maneuver DC 19
Saving Throws Dex +7, Con +10, Int +10, Wis +10
Skills Deception +9, History +10, Intimidation +9, Stealth +7
Damage Resistances poison, psychic
Senses blindsight 30 ft., darkvision 120 ft.,passive Perception 15
Languages Deep Speech, telepathy 120 ft.
Amphibious. The aboleth can breathe air and water.
ACTIONS
Multiattack. The aboleth attacks once with its bite and twice with its tentacles.
Bite. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 32 (4d12 + 6) piercing damage, and the target is grappled (escape DC 19). Until this grapple ends, the target is restrained , and the aboleth can’t bite a different creature.
Tentacle. Melee Weapon Attack: +11 to hit, reach 15 ft., one target. Hit: 20 (4d6 + 6) bludgeoning damage. If the target is a creature, it makes a DC 18 Constitution saving throw . On a failure, it contracts a disease called the Sea Change. On a success, it is immune to this disease for 24 hours. While affected by this disease, the target has disadvantage on Wisdom saving throws. After 1 hour, the target grows gills, it can breathe water, its skin becomes slimy, and it begins to suffocate if it goes 12 hours without being immersed in water for at least 1 hour. This disease can be removed with a disease-removing spell cast with at least a 4th-level spell slot, and it ends 24 hours after the aboleth dies.
BONUS ACTIONS
Ink Jet (Recharge 5–6). While underwater, the aboleth exudes a cloud of inky slime in a 30-foot-radius sphere. The slime extends around corners, and the area is heavily obscured for 1 minute or until a strong current dissipates the cloud. The aboleth then moves up to its speed without provoking opportunity attacks .
In some areas, the aboleth population is dense enough that physical confrontations among their own become commonplace. While aboleth prefer to fight using their more insidious abilities, their fellow aboleths are immune to such tactics. With no other option available, these aboleths turn to their fearsome shark-like teeth and powerful tails to prevail.
Aboleths dwell beneath the Midnight Sea, but their minions explore every part of Underland.
CR 0–2 1 or 2 oculites ; 1d4 slitherwhites
CR 3–4 maw swarm ; 3 or 4 oculites
CR 5–10 aboleth champion
Treasure 150 iron coins (worth 10 gp each, but only to creatures that trade with aboleths); vicious longsword
CR 11–16 aboleth champion with 3 or 4 aboleth thralls , oculites , or slitherwhites ; aboleth brute with 1 or 2 aboleth thralls ; aboleth fallen ascendant
Treasure a barnacled mithral nameplate, torn from an ancient ship, bearing the name Red Queen (worth 5,000 gp), 10 vials of bubbling slime (each acts as a combined potion of greater healing and potion of water breathing )
Aberrations are unnatural beings that don’t belong to this plane of existence. Many aberrations are telepathic and use a mental power known as psionic power instead of magic. An aboleth is an aberration.