Undead Unicorn

Charge. If the undead 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.

Innate Spellcasting. The undead unicorn's innate spellcasting ability is Charisma (spell save DC 16). The undead unicorn can innately cast the following spells, requiring no components:

At will: detect evil and good, druidcraft, pass without trace

1/day each: cause fear, animate dead, entangle

Magic Resistance. The undead unicorn has advantage on saving throws against spells and other magical effects including any effect that turns undead.

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

Marshal Undead. Unless the undead unicorn is incapacitated, it and undead creatures of its choice within 60 feet of it have advantage on saving throws against features that turn undead.

Undead Fortitude. If damage reduces the undead unicorn to 0 hit points, it must make a Constitution saving throw with a DC of 5 + the damage taken, unless the damage is radiant or from a critical hit. On a success, the undead unicorn drops to 1 hit point instead.

Undead Nature. The undead unicorn doesn't require air, food, drink, or sleep.

Multiattack. The undead unicorn makes three attacks: two with its hooves and one with its horn or gory vomit.

Hooves. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 12 (2d6 + 5) bludgeoning damage plus 9 (2d8) necrotic damage.

Horn. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 9 (1d8 + 5) piercing damage plus 9 (2d8) necrotic damage.

The target must succeed on a DC 15 Constitution saving throw or its hit point maximum is reduced by an amount equal to the necrotic damage taken and the undead unicorn regains a number of hit points equal to half of that. This reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0.

A humanoid slain by this attack rises 24 hours later as a zombie under the undead unicorn's control, unless the humanoid is restored to life or its body is destroyed. The undead unicorn can have no more than twelve zombies under its control at one time.

Gory Vomit (Recharge 5–6). The undead unicorn vomits black gore in a 30-foot cone. Each creature in that area must make a DC 15 Constitution saving throw, taking 45 (10d8) necrotic damage on a failed save, or half as much damage on a successful one.

Slick gore covers the ground under the cone and turns it into difficult terrain for 1 minute.

Each creature standing in its area must succeed on a DC 12 Dexterity saving throw or fall prone. A creature that enters the area or ends its turn there must also succeed on a DC 12 Dexterity saving throw or fall prone.

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

The undead 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 undead unicorn makes one attack with its hooves.

Vampiric Shield (Costs 2 Actions). The undead unicorn creates a magical field of black, crackling energy 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 undead unicorn's next turn.

Whenever a creature within 5 feet of the target hits it with a melee attack, the attacker takes 9 (2d8) necrotic damage and the target regains a number of hit points equal to half of that.

Heal Self (Costs 3 Actions). The undead unicorn magically regains 12 (2d8 + 3) hit points.