Magic Resistance. Zrixvyra has advantage on saving throws against spells and other magical effects.

Legendary Resistance (3/Day). If Zrixvyra fails a saving throw, she can choose to succeed instead.

Six Heads (True Form). Zrixvyra has advantage on saves against being blinded, charmed, deafened, frightened, stunned, or knocked unconscious.

Multiattack (True Form). Zrixvyra makes two Claw attacks and one Flurry of Bites attack.

Claw. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 13 (2d6 + 6) slashing damage.

Flurry of Bites. Melee Weapon Attack: +10 to hit, reach 10 ft., one creature. Hit: 27 (6d6 + 6) piercing damage plus 14 (4d6) poison damage.

Constrict (True Form). Melee Weapon Attack: +10 to hit, reach 15 ft., one Large or smaller creature. Hit: 16 (3d6 + 6) bludgeoning damage plus 7 (2d6) acid damage, and the target is grappled (escape DC 16). Until this grapple ends, the target is restrained, and it takes 16 (3d6 + 6) bludgeoning damage plus 7 (2d6) acid damage at the start of each of its turns. Zrixvyra can constrict only one creature at a time.

Spellcasting. Zrixvyra casts one of the following spells, requiring no material components and using Charisma as the spellcasting ability (spell save DC 17):

At will: animal friendship (snakes only), Chill Touch (11th level), Lightning Lure (11th Level)
3/day each: darkness, entangle, Bestow Curse, polymorph C, suggestion, Counterspell, Sickening Radiance C, Cloudkill C
1/day each: Finger of Death, Power Word Pain, Tasha's Otherworldly Guise, Chain Lightning, Mass Suggestion

Change Shape. Zrixvyra transforms into a Huge Anathema snake (True Form) or back into its humanoid form. Its statistics are the same in each form. Any equipment it is wearing or carrying isn’t transformed.

Zrixvyra can take 3 legendary actions, choosing from the options below. She can take only one legendary action at a time and only at the end of another creature’s turn. Zrixvyra regains spent legendary actions at the start of her turn.

Lightning Wrap. When a creature moves within 30 feet of Zrixvyra she can immediately use Lightning Lure

Stalk and Bite (2 actions). Zrixvyra moves up to her max movement speed and makes an attack with flurry of bites.

Triggered Cast (3 actions). Zrixvyra casts any available leveled spell (3/day or 1/day spells)