Urquirsh

 Death Burst. The urquirsh explodes when it dies. Constitution Saving Throw: DC 11, each creature in a 10-foot Emanation originating from the urquirsh. Failure: The target has the Paralyzed condition until the start of its next turn.

Dextrous Maneuverability. The urquirsh's movement ignores Difficult Terrain.

Spider Climb. The urquirsh can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Stench. Constitution Saving Throw: DC 11, any creature (other than an urquirsh) that starts its turn in a 20-foot Emanation originating from the urquirsh. Failure: The target has the Poisoned condition until the start of its next turn. Success: The target is immune to the Stench of all urquirshes for 1 hour.

Multiattack. The urquirsh makes three Mental Rend attacks. It can replace one attack with a use of Vile Miasma.

Mental Rend. Melee Attack Roll: +4, reach 5 ft. Hit: 4 (1d4 + 2) Psychic damage.

Acid Bomb (Recharge 5-6). Dexterity Saving Throw: DC 11, each creature in a 20-foot Sphere centered on a point within 90 feet of the urquirsh. Failure: 14 (4d6) Acid damage and the target must repeat its saving throw against the urquirsh's Stench (unless it is already immune). Success: Half damage only.

Vile Miasma. Dexterity Saving Throw: DC 11, each creature in a 20-foot Cone. Failure: The target makes all d20 Tests using Dexterity with Disadvantage until it or another creature uses its action to scrape the miasma off.