Vile Mucous. Any creature that makes physical contact with the adaru must make a DC 16 Constitution saving throw, taking 16 (3d8 + 3) poison damage on a failed save, or half as much damage on a successful one.

Obyrith Influence. All non-obyrith creatures that start their turns within 60 feet of the adaru or which enter this radius for the first time on a turn must succeed on a DC 15 Wisdom saving throw or have their mind warped by the adaru's presence. The creature gains a unique type of short-term madness in which they hallucinate a vivid odor so acrid and foul that they are unable to willingly stomach food, water, or potions. Additionally, such a creature has disadvantage on Constitution checks and saving throws for the duration of the madness. This madness lasts 5 (1d10) minutes or until cured. A creature that succeeds on the Wisdom saving throw or for whom the madness ends is immune to the adaru's Obyrith Influence for 24 hours.

Multiattack. The adaru makes three attacks, two with its bite and one, if it can, with either its noxious spray or rotting breath.

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., 1 target. Hit: 14 (3d6 + 4) piercing damage plus 15 (2d8 + 6) poison damage. 

Noxious Spray (Recharge 6). The adaru's leech head spits a spray of toxic fluid in a 30-foot cone. Each creature in that area must make a DC 16 Dexterity saving throw, taking 10 (3d6) poison damage plus 10 (3d6) acid damage on a failed save, or half as much damage on a successful one.

Rotting Breath (Recharge 6). The adaru's snake head exhales flesh-rotting gas in a 30-foot cone. Each creature in that area must make a DC 16 Constitution saving throw, taking 22 (5d8) necrotic damage on a failed save, or half as much damage on a successful one.