Medium turned, darkness, aberration,

Armor Class: 16 (Natural Armour)

Hit Points: 93 ( 11d10+33 )

Speed: 30 ft , swim: 30 ft

STR

20 +5

DEX

10 +0

CON

16 +3

INT

5 -3

WIS

11 +0

CHA

5 -3

Skills: Perception +4

Damage Vulnerabilities: Fire

Damage Immunities: Poison

Condition Immunities: Poison

Senses: Darkvision 60ft.

Languages: Common, Aquan

Challenge Rating: 4 ( 1100 XP)

Actions

Multiattack. The chuul makes two pincer attacks. If the chuul is grappling a creature, the chuul can also use its tentacles once.
  Pincer. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 12 (2d6 + 5) bludgeoning damage. The target is grappled (escape DC 14) if it is a Large or smaller creature and the chuul doesn’t have two other creatures grappled.
  Tentacles. One creature grappled by the chuul must succeed on a DC 13 Constitution saving throw or be poisoned for 1 minute. Until this poison ends, the target is paralyzed. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Reactions

Grab. The creature may use its reaction to grab a creature moving out of reach to grab and restrain it. The target makes a DC12 Dexterity Save to avoid the grappling.

Usual Tactics

The creature is somewhat intelligent and will adapt its strategy to fit the fight.
Spellcaster are its primary target, although they may be confused if a person with a lot of magic items is present.