The Calm and the Storm. Zuandril is able to peer into the minds and hearts of any creature within 60 feet of him, this allows him to learn of their deepest fears, regrets, and desires. This allows him to put an image in those creatures minds that depicts him as one of those things, or his true form, a 125-foot-long 20 foot tall conglomerate of gargantuan snakes, ending with the head of snake, with two spider faces on either side. The last 15 feet of Zulandril's true form is a giant stinger, able to inject paralyzing venom into a creature it hits. Until he makes himself known, Zuandril is invisible. A creature can use a bonus action to make a DC 21 Investigation check to determine the true form of Zuandril, if they succeed they can no longer be fooled by his form. Regardless of which form Zuandril appears to be, his stats are always the same.

Jump Scare. Unless a creature is aware of Zuandril's true form, all attacks against them by him are at advantage and all attacks they take against Zuandril are at disadvantage.

Multiattack. Zulandril makes a Snakebite attack, 2 Spiderbite attacks, a Stinger attack, and uses Radiating Fear. Each of the bite attacks must be against different targets

Snakebite. Melee Weapon Attack: +11 to hit, reach 15 ft., 1 target. Hit: 32 (6d8 + 5) piercing damage. 

Spiderbite. Melee Weapon Attack: +11 to hit, reach 10 ft., 1 target. Hit: 9 (1d6 + 5) piercing damage and 14 (4d6) necrotic damage. 

Stinger. Melee Weapon Attack: +11 to hit, reach 25 ft., 1 target. Hit:  22 (3d10 + 5) piercing damage plus 18 (5d6) psychic damage. Creatures hit by this attack must succeed a DC 18 Con save or be paralyzed until the end of their next turn. 

Radiating Fear.  Each creature of Zuandril's choice that is within 120 feet of the dragon  must succeed on a DC 21 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the dragon's Frightful Presence for the next minute. Creatures feared in this way have their movement speed halved, unless they are traveling away from Zuandril.

Zulandril can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. Zulandril regains spent legendary actions at the start of its turn.

Snake Bite. Zulandril makes a snake bite attack.

Stinger (Uses 2 actions). Zulandril makes a stinger attack.

Ever-changing Visage (Uses 3 actions). Zulandril takes a new version of each creature's three essences. Creatures that can see this transformation must succeed a DC 21 Wisdom save or are paralyzed until the start of their next turn.