Slippery Mind. The Yggywog is immune to any effect that would put it to sleep or cause it to act contrary to its nature. It is also immune to the charmed condition.

Slippery. Attack rolls against the Yggywog have disadvantage, and the Yggywog is immune to the grappled and restrained conditions.

Multiattack. The sahuagin makes 3 attacks, only one of which can be its tounge, or it makes 2 attacks and uses its summon frogs.

Bite. Melee Weapon Attack: Reach 5ft, +9 to hit, 2d6 piercing damage + 1d4 poison damage, and the target must succeed on a DC14 constitution saving throw or be poisoned for 1 minute. If the target failed the saving throw by 3 or more, then they are also unconcious for the duration of the poison.

Claws. Melee Weapon Attack: Reach 5ft, +9 to hit, 2d8 slashing damage.

Tounge. Melee Weapon Attack: Reach 15ft, +10 to hit, 1d4 bludgeoning damage + 1d6 poison damage, and the target must succeed on a DC16 constitution saving throw or be poisoned for 1 minute.  If the target failed the saving throw by 3 or more, then they are also unconcious for the duration of the poison. The target is also grappled (escape DC19) if it is of size large or smaller. The Yggywog has advantage on attack rolls against creatures grappled in this way. The Yggywog cannot use its tounge attack if it already has a creature grappled in this way.

Swallow. The Yggywog makes a bite attack against a medium or smaller creature grappled by it. If the attack hits, the target is swallowed and the grappled condition ends on it. While swallowed, a creature takes 2d6 acid damage at the start of each of the Yggywog's turns, is restrained, incapaicated, and blinded, and has total cover from all effects originating outside the Yggywog. A swallowed creature can escape with by spending 15 feet of movement once the Yggywog is dead.

Summon Frogs. The Yggywog magically calls 3d4 giant frogs or 1d4 Sahuagin. The summoned creatures arrive in 1d4-1 rounds, act on initiative count 15, and are under the Yggywog's control.

Slide. The Yggywog moves up to 60ft downhill in addition to its normal movement.