Vecna: Eve of Ruin (5e)
Spellcasting. The dryad casts one of the following spells, requiring no material components and using Charisma as the spellcasting ability (spell save DC 17):
Bramble Walk. Difficult terrain composed of vegetation, such as foliage or thorns, doesn't cost the dryad extra movement.
Magic Resistance. The dryad has advantage on saving throws against spells & other magical effects.
Speak with Beasts & Plants. The dryad can communicate with Beasts & Plants as if they shared a language.
Multiattack. The dryad makes two Poisonous Thorn attacks & one Sapping Vine attack.
Poisonous Thorn. Melee or Ranged Weapon Attack: +8 to hit, reach 5 ft. or range 120 ft., one target. Hit: 13 (4d4 + 3) piercing damage plus 10 (3d6) poison damage. If the target is a creature, it must succeed on a DC 17 Constitution saving throw or have the poisoned condition until the start of the dryad's next turn.
Sapping Vine. Melee Weapon Attack: +8 to hit, reach 30 ft., one target. Hit: The target has the grappled condition (escape DC 16). Until the grapple ends, the target has the restrained condition, & the dryad can't use the same vine on another target. A creature restrained in this way takes 13 (3d8) necrotic damage at the start of its turn.
The dryad has six vines. Each vine can be attacked (AC 20; 10 hit points; immunity to poison & psychic damage). Destroying a vine deals no damage to the dryad, but any creature grappled by that vine no longer has the grappled condition. All vines immediately wither & disappear when the dryad is reduced to 0 hit points.
Any Climate; Forests, Swamps, Wastelands; Feywild