Amphibious. The kuo-toa can breathe air and water.
Otherworldly Perception. The kuo-toa can sense the presence of any creature within 30 feet of it that is invisible or on the Ethereal Plane. It can pinpoint such a creature that is moving.
Slippery. The kuo-toa has advantage on ability checks and saving throws made to escape a grapple.
Sunlight Sensitivity. While in sunlight, the kuo-toa has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.
Unarmored Defense. The kuo-toa adds its Wisdom modifier to its armor class.
Multiattack. The kuo-toa makes one bite attack and two unarmed strikes.
Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit:4 (1d4 + 2) piercing damage.
Unarmed Strike. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit:5 (1d6 + 2) bludgeoning damage plus 3 (1d6) lightning damage, and the target can't take reactions until the end of the kuo-toa's next turn.
Kuo-toa are degenerate fishlike humanoids that once inhabited the shores and islands of the surface world. Long ago humans and their ilk drove the kuo-toa underground, where they dwell in madness and everlasting night. Kuo-toa can no longer abide daylight.