Huge monstrosity, neutral

Hold Breath The Petsuchos can hold its breath for 15 minutes.

Instill Doubt (3/day) The Petsuchos can use a bonus action to target one creature within 30 feet of it. If the target can hear the Petsuchos, the target must succeed on a DC 11 Charisma saving throw or have disadvantage on ability checks, attack rolls, and saving throws until the start of the Petsuchos's next turn

Actions

Multiattack. The Petsuchos makes two attacks: one with its bite and one with its tail.

Bite. Melee Weapon Attack: +8 to hit, Reach 5ft., one creature. 21 (3d10 + 5) piercing damage, and the target is grappled (escape DC 16). Until this grapple ends, the target is restrained, and the Petsuchos can’t bite another target.

Tail. Melee Weapon Attack: +8 to hit, Reach 10ft., one target not grappled by the Petsuchos. 15 (2d8 + 5) bludgeoning damage (escape DC 16). If the target is a creature, it must succeed on a DC 16 Strength saving throw or be knocked prone.

Roaring Sunlight Cannon (Recharge 6). A line of pure roaring sunlight 200 feet long and 5 feet wide emanates from the Persuchos in a direction of its choice. The creatures hit within the line must succeed on a DC 15 Constitution saving throw . A creature takes 8d10 radiant damage on a failed save or half as much on a successful one.