Chuul Monstrosity

Limited Telepathy. The chuul monstrosity can magically transmit simple messages and images to any creature within 120 feet of it that can understand a language. This form of telepathy doesn't allow the receiving creature to telepathically respond.

Amphibious. The chuul monstrosity can breathe air and water.

Sense Magic. The chuul monstrosity senses magic within 120 feet of it at will. This trait otherwise works like the detect magic spell but isn't itself magical.

Multiattack. The chuul monstrosity makes four attacks: two with its pincers and two with its tentacles.

Pincer. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 11 (2d6 + 4) bludgeoning damage. The target is grappled (escape DC 13) if it is a Large or smaller creature and the chuul monstrosity doesn't have two other creatures grappled.

Tentacle. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 7 (1d8 + 4) bludgeoning damage plus 4 (1d8) piercing damage. If the target is Medium or smaller, it is grappled (escape DC 13) and restrained until the grapple ends. The chuul monstrosity has two tentacles, each of which can grapple one target.

Slam. The chuul monstrosity slams creatures grappled by it into each other or a solid surface. Each creature must succeed on a DC 14 Constitution saving throw or take 10 (2d6 + 4) bludgeoning damage and be stunned until the end of the chuul monstrosity's next turn. On a successful save, the target takes half the bludgeoning damage and isn't stunned.