Black Unicorn

Charge. If the black unicorn 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 (2d8) piercing damage. If the target is a creature, it must succeed on a DC 15 Strength saving throw or be knocked prone. If the black unicorn is in a Hornless Rage, it can swap the horn attack for a headbutt attack and deal an extra 9 (2d8) bludgeoning damage.

Innate Spellcasting. The black unicorn’s innate spellcasting ability is Charisma (spell save DC 15). The unicorn can innately cast the following spells, requiring no components:

At will: cause fear, poison spray, pass without trace

1/day each: crown of madness, contagion, entangle

Magic Weapons. The black unicorn’s weapon attacks are magical.

Hornless Rage. The black unicorn’s horn can be removed with a DC 19 Strength (Athletics) throw. Without its horn, the black unicorn's melee attacks deal +3 additional damage and it is resistant to all bludgeoning, piercing and slashing damage. Furthermore it loses its Innate Spellcasting abilities and all actions and legendary actions except for the multiattack and hooves attack. It gains the headbutt attack.

Sickening Aura. Any creature that starts its turn within 15 feet of the black unicorn must succeed on a DC 13 Constitution saving throw or be poisoned until the start of the creatures next turn. On a successful saving throw, the creature is immune to this effect for 12 hours.

Multiattack. The black unicorn 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 + 4) bludgeoning damage.

Horn. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) piercing damage plus 3 (1d6) poison damage.

Headbutt (Hornless Rage only). Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) bludgeoning damage.

Draining Touch (3/Day). The black unicorn touches another creature with its horn. The target must make a DC 13 Constitution saving throw, taking 20 (4d8 + 2) necrotic damage or half as much damage on a successful save. The target's hit point maximum is reduced by an amount equal to the damage taken. This reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0.

Teleport (1/Day). The black unicorn 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 black unicorn is familiar with, up to 1 mile away.

The black unicorn can take 3 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 unicorn regains spent legendary actions at the start of its turn.

Hooves. The unicorn makes one attack with its hooves.

Flaring Shield (Costs 2 Actions). The black unicorn creates a flaring, magical field around itself or another creature it can see within 60 feet of it. The target gains a +2 bonus to AC until the end of the unicorn’s next turn.

Heal Self (Costs 3 Actions). The unicorn magically regains 11 (2d8 + 2) hit points or 20 (4d8 + 2) hit points if it used its Draining Touch action in the last round.