Vampiric-Beholder-Headed-Hydra

Antimagic Cone. The central eye of the creature's head creates an area of antimagic, as in the antimagic field spell, in a 150-foot-cone. At the start of each of its turns, the creature decides which way the cone faces and whether the cone is active. The area works against the creature's own eye rays.

Multiple Heads. The creature has five heads. While it has more than one head, the creature has advantage on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious.

Whenever the creature takes 50 or more damage in a single turn, one of its heads dies. If all its heads die, the creature transforms in to a large size cloud of mist as it's Misty Escape trait.

At the end of its turn, it grows two heads for each of its heads that died since its last turn, unless it has taken radiant damage since its last turn. The creature regains 10 hit points for each head regrown in this way. 

This creature also has advantage on any perception checks made to spot enemies as it has not only multiple heads, but each head has 10 different eye stalks constantly monitoring it's surroundings. 

Wakeful. While the creature sleeps, at least one of its heads is awake.

Hold Breath. The creature can hold its breath for 1 hour. 

Legendary Resistance (3/Day). If the creature fails a saving throw, it can choose to succeed instead.

Regeneration. The creature regains 20 hit points at the start of its turn if it has at least 1 hit point and isn't in sunlight. If the creature takes radiant damage or damage from holy water, this trait doesn't function at the start of the creature's next turn.

Spider Climb. The creature can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Shapechanger. If the creature isn't in sunlight, it can use its action to polymorph into a huge cloud of mist, or back into its true form.

While in mist form, the creature can't take any actions, speak, or manipulate objects. It is weightless, has a flying speed of 20 feet, can hover, and can enter a hostile creature's space and stop there. In addition, if air can pass through a space, the mist can do so without squeezing, and it can’t pass through water. It has advantage on Strength, Dexterity, and Constitution saving throws, and it is immune to all nonmagical damage, except the damage it takes from sunlight.

Misty Escape. When it drops to 0 hit points outside its lair, the creature transforms into a cloud of mist (as in the Shapechanger trait) instead of falling unconscious, provided that it isn't in sunlight. If it can't transform, it is destroyed.

While it has 0 hit points in mist form, it can't revert to its creature form, and it must reach its lair within 6 hours or be destroyed. Once in its lair, it reverts to its creature form. It is then  paralyzed until it regains at least 1 hit point. After spending 1 hour in its lair with 0 hit points, it regains 1 hit point. If it was killed by decapitation, then it instead regains 2 heads and 10 hit points. 

Vampiric Weaknesses. The creature  has the following flaws:

Forbiddance. The creature can't enter a residence without an invitation from one of the occupants.

Sunlight Hypersensitivity. The creature takes 20 radiant damage when it starts its turn in sunlight. While in sunlight, it has disadvantage on attack rolls and ability checks. 

Stake to the Heart. If a large or larger piercing weapon made of wood is driven into the creature's heart while the creature is  incapacitated in its resting place, the creature is  paralyzed until the weapon is removed.

Multiattack. The creature can make a number of eye-ray attacks equal to the number of heads it currently has, or a number of bite attacks equal to the number of heads it has with the ability to exchange any bite attack for a charm attack.

Charm. The creature targets one humanoid it can see within 30 feet of it. If the target can see the creature, the target must succeed on a DC 19 Wisdom saving throw against this magic or be charmed by the Creature. The charmed target regards the creature as a trusted friend to be heeded and protected. Although the target isn't under the creature's control, it takes the creature's requests or actions in the most favorable way it can, and it is a willing target for the creature's bite attack.

Each time the creature or the creature's companions do anything harmful to the target, it can repeat the saving throw, ending the effect on itself on a success. Otherwise, the effect lasts 24 hours or until the creature is destroyed, is on a different plane of existence than the target, or takes a bonus action to end the effect.

If the target succeeds on their wisdom saving throw, they are immune to the creature's charm until the start of the creature's next turn.

Bite.  Melee Weapon Attack: +11 to hit, reach 10 ft. Hit: 18 (4d6 + 5) piercing damage plus 10 (3d6) necrotic damage. The target's hit point maximum is reduced by an amount equal to the necrotic damage taken, and the creature regains hit points equal to that amount. The 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 in this way and then buried in the ground rises the following night as a vampire spawn under the creature's control.

Eye Rays. The creature shoots the following magical eye rays at random (reroll any duplicates per head), choosing any number of targets it can see within 120 feet of it:

1. Charm Ray. The target must succeed on a DC 19 Wisdom saving throw or be charmed by the creature for 1 hour, or until the creature harms the target.

2. Paralyzing Ray. The targeted creature must succeed on a DC 19 Constitution saving throw or be paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

3. Fear Ray. The targeted creature must succeed on a DC 19 Wisdom saving throw or be frightened for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

4. Slowing Ray. The targeted creature must succeed on a DC 19 Dexterity saving throw. On a failed save, the target’s speed is halved for 1 minute. In addition, the creature can’t take reactions, and it can take either an action or a bonus action on its turn, not both. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

5. Enervation Ray. The targeted creature must make a DC 19 Constitution saving throw, taking 36 (8d8) necrotic damage on a failed save, or half as much damage on a successful one.

6. Telekinetic Ray. If the target is a creature, it must succeed on a DC 19 Strength saving throw or the creature moves it up to 30 feet in any direction. It is restrained by the ray’s telekinetic grip until the start of the creature's next turn or until the creature is incapacitated.

If the target is an object weighing 300 pounds or less that isn’t being worn or carried, it is moved up to 30 feet in any direction. The creature can also exert fine control on objects with this ray, such as manipulating a simple tool or opening a door or a container.

7. Sleep Ray. The targeted creature must succeed on a DC 19 Wisdom saving throw or fall asleep and remain unconscious for 1 minute. The target awakens if it takes damage or another creature takes an action to wake it. This ray has no effect on constructs and undead.

8. Petrification Ray. The targeted creature must make a DC 19 Dexterity saving throw. On a failed save, the creature begins to turn to stone and is restrained. It must repeat the saving throw at the end of its next turn. On a success, the effect ends. On a failure, the creature is petrified until freed by the greater restoration spell or other magic.

9. Disintegration Ray. If the target is a creature, it must succeed on a DC 19 Dexterity saving throw or take 45 (10d8) force damage. If this damage reduces the creature to 0 hit points, its body becomes a pile of fine gray dust.

If the target is a Large or smaller nonmagical object or creation of magical force, it is disintegrated without a saving throw. If the target is a Huge or larger object or creation of magical force, this ray disintegrates a 10-foot cube of it.

10. Death Ray. The targeted creature must succeed on a DC 19 Dexterity saving throw or take 55 (10d10) necrotic damage. The target dies if the ray reduces it to 0 hit points.

Reactive Heads. For each head the creature has beyond one, it gets an extra reaction that can be used only for opportunity attacks.

The creature 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 creature regains spent legendary actions at the start of its turn.

Eye Ray. The creature uses one random eye ray.

Bite. (Costs 2 Actions). The creature makes one bite attack.

 Move. The creature moves up to its speed without provoking opportunity attacks.