Annihilator

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

Innate Tracking. The annihilator has advantage on Wisdom (Survival) checks to track creatures by scent.

Spider Climb. The annihilator can move up, down, and across vertical surfaces and upside down along ceilings.

Alien Mind. The annihilator is immune to effects that read thoughts, determine alignment, or detect lies. Attempts to do so cause the creature to experience brief, disorienting static (DC 15 Wisdom save or be stunned until the end of their next turn).

Multiattack. The annihilator makes two Antennae Touch attacks.

Antennae Touch. Melee Spell Attack: +10 to hit, reach 5 ft., one creature or object.
Hit (Creature): The target must succeed on a DC 16 Constitution saving throw or be disintegrated. A creature disintegrated by this attack, along with all nonmagical gear, is reduced to a pile of dust. On a success, the target takes 17 (5d6) force damage.

Hit (Magic Item): If the target is a magic item or an item worn/carried by a creature, the item must make a DC 21 Dexterity saving throw (using its wielder’s saving throw bonus, or +0 if unattended). On a failure, it is subject to the effects of a disintegrate spell and is destroyed. Artifacts and legendary items automatically succeed on this save.

The annihilator can take 2 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature’s turn. The annihilator regains spent legendary actions at the start of its turn.

Detect (Costs 1 Action). The annihilator makes a Wisdom (Perception) check.
Move (Costs 1 Action). The annihilator moves up to its speed without provoking opportunity attacks.
Lash (Costs 1 Action). The annihilator makes one Antennae Touch attack.