Actions

Multiattack. Yibyiru makes three attacks, one of which may be Spew Bile.

 

Animating Spores. Yibyiru can reanimate the corpse of a humanoid or monstrosity as a spore servant. The reanimated creature regains 50% of its maximum hp. A spore servant has the same game statistics as the base creature except that the reanimation causes its creature type to become undead. Yibyiru has a telepathic link with a spore servant raised with Animating Spores as long as they are on the same plane of existence. She can use this telepathic link to issue commands to the spore servant while she is conscious (no action required), which it does its best to obey. If the spore servant completes its order and doesn't receive further direction from Yibyiru, it defends and preserves itself to the best of its ability. Yibyiru can maintain a maximum of 3 spore servants simultaneously. If she attempts to animate a fourth, all current spore servants are immediately reduced to 0 hp and are no longer under her control.

Toxic Swipe. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 14 (2d10 + 3) slashing damage plus 7 (2d6) poison damage. Unnaturally fast-growing fungi anchor the target to the nearest surface, causing the target to be grappled (escape DC 19).

Spew Bile. Yibyiru targets one creature she can see within 120 feet of her. The target must succeed on a DC 19 Dexterity saving throw or take 11 (3d6) acid damage and 11 (3d6) poison damage.

Sudden Wasting (Recharge 5-6). One creature of Yibyiru's choice within 5 feet of Yibyiru may expend any number of hit dice to heal itself (without adding its Constitution modifier), then Yibyiru may force it to make a DC 19 Constitution saving throw. The target takes 77 (14d10) necrotic damage, or half as much on a success. If the target is killed by this damage, its flesh rots away into a putrid slurry, and Yibyiru can immediate expend a Legendary Action to use Fungal Burst centered on the creature's corpse.

Bonus Actions

Command Servant. Yibyiru commands one spore servant under her control to make one weapon attack. This attack uses the spore servant's reaction.

Reactions

Brainrot (1/Day). When Yibyiru is below 50% of her maximum hp, she can force one creature she can see within 60 feet to make a DC 19 Constitution saving throw. On a failed save, the creature contracts Brainrot, a virulent disease that causes it to become hostile to all creatures for the next minute. At the end of the minute, the target dies. This effect can be removed by any effect that cures disease, and any creature immune to disease is unaffected by Brainrot.

Corpse Detonation. When a spore servant under Yibyiru's control is reduced to 0 hp, she can cause it to explode. Each creature that isn't an undead, fiend, or plant within 5 feet of the exploding spore servant must make a DC 19 Dexterity saving throw, taking 14 (4d6) poison damage on a failed save, or half as much damage on a success.

Mycellia Snare. When a creature ends its turn within 15 feet of an area affected by Fungal Burst, Yibyiru can force it to roll a DC 19 Strength saving throw or fall prone and be dragged up to 15 feet towards the area.

Legendary Actions

Yibyiru can take 3 legendary actions, choosing from the options below.

 

Toxic Swipe. Yibyiru makes one Claw attack against a creature in her reach, or against a creature she can see in an area affected by Fungal Burst.

Parasitic Ruin. One creature grappled by Yibyiru's Toxic Swipe takes 11 (2d10) necrotic damage. A creature that takes 15 or more damage from a use of this ability becomes restrained for as long as it remains grappled.

Fungal Burst (Costs 2 Actions). A roiling growth of multifarious fungus that lasts for a minute bursts forth in a 5 foot radius centered on a point Yibyiru can see within 120 feet. The area is difficult terrain for creatures other than demons, undead, and plants. All other creatures that starts their turns in the area takes 20 poison damage. This effect ends if the area is dealt 20 or more fire or radiant damage from a single source.

Spore Rebirth (Costs 3 Actions). Yibyiru uses Animating Spores.

Lair Actions

If encountered in Zuggtmoy’s fungal domain while Zuggtmoy is not within 6 miles of the lair, Yibyiru taps into the diseased energies of her master's seat of power. On initiative count 20 (losing initiative ties), Yibyiru can use one of the following effects:

 

Blinding Blossom. Fungi erupt in a 15-foot cube that Yibyiru can see within 120 feet. All creatures in the cube must make a DC 17 Dexterity saving throw or be blinded by spores until the end of their next turn.

Fungal Phantasm. Yibyiru expels a cloud of fungal spores in a 20-foot radius sphere centered on a point she can see within 120 feet. Each creature that isn't an undead, fiend, or plant within in the radius must make a DC 19 Constitution saving throw, taking 14 (4d6) poison damage on a failed save, or half as much damage on a success. A creature that fails its saving throw also experiences a mushroom-induced hallucination, as determined by rolling on the Fungal Phantasm table below. The Fungal Phantasm lasts until the end of the creature's next turn or can be removed early by any effect that cures a poison or disease.