Unicorruptor

Charge. If the unicorruptor moves at least 20 feet straight toward a target and then hits it with a horn attack on the same turn, the target takes an extra 9 (2d6) piercing damage. If the target is a creature, it must succeed on a DC 15 Strength saving throw or be knocked prone.

Innate Spellcasting. The unicorruptor's innate spellcasting ability is Charisma (spell save DC 14). The unicorn can innately cast the following spells, requiring no components:

At will: eldritch blast, [/spell], pass without trace

1/day each: bestow curse, fear, darkness,command

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

Magic Weapons. The unicorn's weapon attacks are magical.

Multiattack. The unicorruptor makes two attacks: one with its hooves and one with its horn.

Hooves. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 2) Slashing damage.

Horn.  Melee weapon attack:  +7 to hit, reach 5 ft. one target. hit: 10 (1d8+4) piercing damage

Horn spike(1/day). Ranged Weapon Attack: +7 to hit, reach 30 ft., one target. Hit: 13 (2d6 + 4) piercing damage. The unicorruptor ejects it's horn at high velocity. the horn regrows at dusk.

Teleport (1/Day). The unicorruptor magically teleports itself and up to three willing creatures it can see within 5 feet of it, along with any equipment they are wearing or carrying, to a location the unicorn is familiar with, up to 1 mile away.

Blip (3/day).  If the unicorruptor succeeds a DEX check, it can warp out of the space it was attacked from and appear right behind the attacker.

Counterspell (3/day)

The unicorruptor can take 4 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The unicorruptor regains all spent legendary actions after 3 turns.

Swift hoove slash. The unicorruptor makes (1d6) +DEX modifier attacks with its hooves, dealing (rolled number)d6+4 slashing damage.

Sanguine Shield. The unicorruptor creates a sanguine, magical field around itself or another creature it can see within 30 feet of it. The target gains a +6 bonus to AC until the end of the unicorruptor's next turn.

Heal Self (Costs 2 Actions). The unicorruptor magically regains 8 (1d10 + 2) hit points.

Psychic rage (cost 3 actions). The unicorrupter wails a Horrid cry dealing a full (1d12 + 2) psychic damage or half as much on a successful WIS save. The unicorruptor gains a +7 to strength and +10ft. to walking speed for the next 5 minutes. It cannot reuse this action until after the spell wears off plus (1d8) minutes.