Murgrik

Blood Frenzy. The murgrik has advantage on melee attack rolls against any creature that doesn't have all its hp.

Hold Breath. The murgrik can hold its breath for 30 minutes.

Keen Scent. The murgrik has advantage on Wisdom (Perception) checks that rely on smell.

Tentacle Flight. The murgrik flies by spinning its tentacles. If it is grappling a creature with its tentacles, its flying speed is halved.

Multiattack. The murgrik makes three attacks: one with its bite and two with its tentacles.

Bite. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 15 (2d8 + 6) piercing damage.

Tentacles. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 9 (1d6 + 6) bludgeoning damage. The target is grappled (escape DC 18) if it is a Medium or smaller creature and the murgrik doesn't have two other creatures grappled. Until this grapple ends, the target is restrained.

Stomach Maw. The murgrik makes one bite attack against a Medium or smaller target it is grappling. If the attack hits, the target is also swallowed, and the grapple ends. While swallowed, the target is blinded and restrained, it has total cover against attacks and other effects outside the murgrik, and it takes 14 (4d6) acid damage at the start of each of the murgrik's turns. The murgrik can only have one creature swallowed at a time. If the murgrik takes 20 damage or more on a single turn from the swallowed creature, the murgrik must succeed on a DC 14 Constitution saving throw at the end of that turn or regurgitate the creature, which falls prone in a space within 5 feet of the murgrik. If the murgrik dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 10 feet of movement, exiting prone.

Unsettling Ululations (Recharge 6). The stalk on the murgrik's head unleashes a dispiriting wail. Each creature within 30 feet of the murgrik that can hear it must make a DC 14 Wisdom saving throw. On a failure, a creature takes 21 (6d6) psychic damage and is frightened for 1 minute. On a success, a creature takes half the damage and isn't frightened. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.