Adult Slime Dragon

Adhesive Hide. Strength Saving Throw: DC 18, one creature that hits the dragon with a melee attack roll. Failure: The target is Disarmed of the weapon used in the attack, which can be removed from the dragon's hide by using an action to make a DC 18 Strength (Athletics) check.

Legendary Resistance (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.

Multiattack. The dragon makes three Rend attacks.

Rend. Melee Attack Roll: +10, reach 10 ft. Hit: 16 (2d10 + 5) Slashing damage plus 5 (2d4) Acid damage.

Gooey Breath (Recharge 5–6). Dexterity Saving Throw: DC 17, each creature in a 60-foot Cone. Failure: 33 (6d10) Psychic damage, and the target is engulfed (the dragon can have up to three creatures engulfed at a time). An engulfed target can still breathe, but can’t cast spells with a Verbal component, has the Restrained condition, and takes 10 (3d6) Acid damage at the start of each of the dragon's turns. When the dragon moves, the engulfed target moves with it. An engulfed target can try to escape by taking an action to make a DC 17 Strength (Athletics) check. On a successful check, the target escapes and enters the nearest unoccupied space. Success: Half damage, and the target moves to an unoccupied space within 5 feet of the dragon. If there is no unoccupied space, the target fails the save instead.

If the dragon takes 30 damage or more on a single turn from a creature inside it, the dragon must succeed on a DC 20 Constitution saving throw at the end of that turn or regurgitate all engulfed creatures, each of which falls in a space within 10 feet of the dragon and has the Prone condition. If the dragon dies, any swallowed creature no longer has the Restrained condition.

Legendary Action Uses: 3 (4 in Lair). Immediately after another creature’s turn, the dragon can expend a use to take one of the following actions. The dragon regains all expended uses at the start of each of its turns.

Shockwave. The dragon jumps 40 feet to a space it can see. Dexterity Saving Throw: DC 17, each creature in a 10-foot-radius Sphere centered on the dragon. Failure: 17 (5d6) Bludgeoning damage. Failure or Success: The target is pushed 5 feet away from the dragon, and the dragon can’t take this action again until the start of its next turn.

Pheremone Cloud. The dragon casts Hypnotic Pattern, requiring no Material components and using Charisma as the spellcasting ability (spell save DC 17). The dragon can’t take this action again until the start of its next turn.

Pounce. The dragon makes one Rend attack.