monster

Arasta

CR 21

Huge Monstrosity, Neutral Evil

Reveal Stat Block

Armor Class

19 (natural armor)

Hit Points

300 (24d12 + 144)

Speed

40 ft., climb 40 ft.

str

dex

con

int

wis

cha

Traits

Armor of Spiders (Mythic Trait; Recharges after a Short or Long Rest).If Arasta is reduced to 0 hit points, she doesn't die or fall unconscious. Instead, she regains 200 hit points. In addition, Arasta's children immediately swarm over her body to protect her, granting her 100 temporary hit points.

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

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

Spider Climb.Arasta can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Web Walker.Arasta ignores movement restrictions caused by webbing.

Actions

Multiattack.Arasta makes three attacks: one with her bite and two with her claws.

Bite.mw 14 to hit, reach 5 ft., one creature. ({@damage 3d8 + 7) piercing damage, and the target must make a 21 Constitution saving throw, taking 32 (5d12) poison damage on a failed save, or half as much damage on a successful one. If the damage reduces the target to 0 hit points, the target is stable but poisoned for 1 hour, even after regaining hit points, and is paralyzed while poisoned in this way.

Claws.mw 14 to hit, reach 5 ft., one target. ({@damage 3d6 + 7) slashing damage.

Web of Hair 4.Arasta unleashes her hair in the form of webbing that fills a 30-foot cube next to her. The web is difficult terrain||3, its area is lightly obscured, and it lasts for 1 minute. Any creature that moves into the web or that starts its turn there must make a 21 Dexterity saving throw. On a failed save, the creature is restrained while in the web. A creature can use an action to make a 21 Strength check. On a success, it can free itself or a creature within 5 feet of it that is restrained by the web. This webbing is immune to all damage except magical fire. A 5-foot cube of the web is destroyed if it takes at least 20 fire damage from a spell or other magical source on a single turn.

Legendary Actions.The creature can take 3 legendary actions...

Claws.Arasta makes one attack with her claws.

Swarm (Costs 2 Actions).Arasta causes two swarm of spiders||swarms of spiders to appear in unoccupied spaces within 5 feet of her.

Toxic Web (Costs 3 Actions).Each creature restrained by Arasta's Web of Hair takes 18 (4d8) poison damage.

Arasta

A victim of the gods' petty rivalries, Arasta was once one of Nylea's most beloved dryad companions. Phenax's bitterness saw her transformed into an arachnid monstrosity and driven into the darkest depths of the Nessian Wood. Now she broods on her unjust fate and the fickleness of the gods who left her cursed with monstrous immortality.

Arasta appears as a gigantic spiderlike creature, her few humanoid features made monstrous by cruel magic and ages of hatred. Webs fill her lair deep in the Nessian Wood, sticky strands made not of silk but of her own endless hair. In her darkened realm, Arasta broods on her hatred of the gods and their servants. She doesn't do so alone, though, as innumerable arachnids fawn over her, serving as her eyes throughout the wilderness, disposing of victims trapped within her hair, and sacrificing themselves in her defense if they must.

See 'Myths of Nylea' in chapter 2 for more details on the tragedy of Arasta.