Weave Elemental

Greater Magic Resistance. The elemental automatically succeeds on saving throws against spells and other magical effects, and the attack rolls of spells automatically miss it.

Legendary Resistance (5/Day). If the elemental fails a saving throw, it can choose to succeed instead.

Wild Magic Decay. The elemental emanates an aura in a 20-foot Emanation while it is Bloodied. Constitution Saving Throw: DC 19, each creature that casts a spell in the area. Failure: The action, Bonus Action, or Reaction used to cast the spell is wasted. Failure by 5 or More: The action, Bonus Action, or Reaction used to cast the spell is wasted, and the target takes 3 (1d6) Force damage per level of the spell. Success: The spell is cast as normal. Success by 5 or More: The spell is cast as normal, and the target regains 3 (1d6) Hit Points per level of the spell.

Multiattack. The elemental makes three Arcane Burst attacks or uses Weave Tear twice.

Arcane Burst. Melee or Ranged Attack Roll: +11, reach 5 ft. or range 120 ft. Hit: 38 (6d10 + 5) Force damage.

Weave Tear. The elemental conjures one of the following magical effects at a target it can see within 150 feet of itself (roll 1d8; reroll if the elemental has already used that effect during this turn):

1: Bannishing Abjuration. Charisma Saving Throw: DC 19. Failure: 26 (4d12) Force damage, and the target is banished to a harmless demiplane until the end of its next turn. While there, it has the Incapacitated condition. Success: Half damage only.
2: Teleporting Conjuration. Strength Saving Throw: DC 19. Failure: 26 (4d12) Force damage, and the target is teleported up to 60 feet to an unoccupied space on the ground the elemental can see. Failure by 5 or More: The target is teleported to an unoccupied space within 120 feet instead of 60 feet. Success: Half damage only.
3: Illuminating Divination. Wisdom Saving Throw: DC 19. Failure: 26 (4d12) Radiant damage, and the target can’t benefit from the Invisible condition until the end of its next turn. Success: Half damage only.
4: Charming Enchantment. Wisdom Saving Throw: DC 19. Failure: 26 (4d12) Psychic damage, and the target has the Charmed condition until the end of its next turn. Success: Half damage only.
5: Blinding Evocation. Dexterity Saving Throw: DC 19. Failure: 26 (4d12) damage of a type chosen by the elemental: Acid, Cold, Fire, Lightning, or Thunder. If the target is a creature, it has the Blinded condition until the end of its next turn. Success: Half damage only.
6: Terrifying Illusion. Intelligence Saving Throw: DC 19. Failure: 26 (4d12) Psychic damage, and the target has the Frightened condition until the end of its next turn. Success: Half damage only.
7: Vampiric Necromancy. Constitution Saving Throw: DC 19. Failure: 26 (4d12) Necrotic damage, and the target can't regain Hit Points until the end of its next turn. Success: Half damage only. Failure or Success: The elemental regains Hit Points equal to the amount of Necrotic damage dealt.
8: Petrifying Transmutation. Constitution Saving Throw: DC 19. First Failure: 26 (4d12) Force damage, and the target has the Restrained condition and repeats the save at the end of its next turn if it is still Restrained, ending the effect on itself on a success. Second Failure: The target has the Petrified condition instead of the Restrained condition for 1 minute, and the target repeats the save at the end of each of its turns, ending the effect on itself on a success. After 1 minute, it succeeds automatically. Success: Half damage only.

Legendary Action Uses: 3. Immediately after another creature’s turn, the elemental can expend a use to take one of the following actions. The elemental regains all expended uses at the start of each of its turns.

Sickening Spray. The elemental makes two Arcane Burst attacks. If the elemental makes both attacks against the same target, it has the Poisoned condition until the end of its next turn.

Weave Overload. The elemental uses Weave Tear, and the target gains 1 level of Exhaustion. The elemental can’t take this action again until the start of its next turn.