Legendary Resistance (4/Day, or 5/Day in Lair). If Zuggtmoy fails a saving throw, she can choose to succeed instead.

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

Demonic Restoration. If Zuggtmoy dies outside the Abyss, her body dissolves into ichor, and she gains a new body instantly, reviving with all her Hit Points somewhere in the Abyss.

Multiattack. Zuggtmoy makes three Pseudopod attacks. It can replace one attack with a use of spellcasting to cast blight.

Pseudopod. Melee Weapon Attack: +13 to hit, reach 10 ft. or range 60ft. Hit: 18 (2d8 + 9) force damage plus 9 (2d8) poison damage.

Spellcasting. Zuggtmoy casts one of the following spells, requiring no Material components and using Charisma as the spellcasting ability (spell save DC 23, +15 to hit with spell attacks):
At will: blight, fear, plant growth
1/Day Each: contagion, confusion (Level 5 version), charm monster

Infestation Spores (3/Day). Zuggtmoy releases spores in a 20-ft radius sphere that lasts 1 minute. Creatures in or entering the cloud must make DC 20 CON save. Success grants 24h immunity; failure infects with spores of Zuggtmoy until cured or death. Infected creatures can't be reinfected and must save at the end of each 24h. On success, infection ends. After 3 failed saves, creature dies and reanimates as a myconid spore servant if compatible.

Mind Control Spores (Recharge 5-6). Zuggtmoy releases spores in a 20-ft radius sphere that lasts 1 minute. Humanoids and beasts in or entering the cloud must make DC 20 WIS save or be infected with Influence of Zuggtmoy for 24h, becoming charmed. Success grants 24h immunity.

Protective Thrall. When Zuggtmoy is hit by an attack roll, one creature within 10 feet of her that is charmed by her is hit by the attack instead.

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

Exert Will: Up to four plant creatures that are friendly to Zuggtmoy and that Zuggtmoy can see can use their reactions to move up to their speed and make one weapon attack.

Summon Fungi (Recharge 3-4): Zuggtmoy causes four gas spore fungus or violet fungus to appear in unoccupied spaces that she chooses within 120 feet.

Unleash Spores. Zuggtmoy uses her Mind Control Spores centered on a mushroom or other fungus within 60 feet instead of on herself.