BeHydra

Antimagic Cone. The BeHydra has a giant eye in the middle of its chest that creates an area of antimagic, as in the antimagic field spell, in a 80-foot-cone. At the start of each of its turns, the BeHydra decides whether the cone is active or not and the cone always is to where the BeHydra is facing. The area works against the BeHydras own eye rays.

Poisoned Blood. When the BeHydra takes piercing or slashing damage, each creature within 5 feet of the hydra takes 12 (2d10) poison damage.

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

Multiple Heads. The BeHydra has three heads at the start. While it has more than one head, the BeHydra has advantage on saving throws against being blinded, charmed, deafened, frightened, stunned, or knocked unconscious.

Whenever the BeHydra takes 40 or more damage in a single turn, one of its heads dies. If all its heads die, the hydra dies.

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 fire damage since its last turn. The BeHydra regains 20 hit points for each head regrown in this way.

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

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

Magic Weapons. The Behydra attacks are considered magical.

Legendary Resistance (5/Day). If BeHydra fails a saving throw, it can choose to succeed instead.

Multiattack. The BeHydra makes as many bite attacks as it has heads and one tail attack.

Tail. Melee Weapon Attack: +15 to hit, reach 25 ft., one target. Hit: 28 (4d8 + 10) piercing damage.

Bite. Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 21 (3d10 + 6) piercing damage. When bitten by the BeHydra the creature takes an additional 5 poison damage.

Eye Rays. The BeHydra shoots three of the following magical eye rays at random instead of using the Bite attack. For each head spawned it can make an extra ray. random (reroll duplicates), choosing one to three targets it can see within 150 feet of it:

1. 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.

    

2. 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.

    

3. Enervation Ray. The targeted creature must make a DC 19 Constitution saving throw, taking 40 (8d8) necrotic damage on a failed save, or half as much damage on a successful one.

    

4. 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.

    

5. Disintegration Ray. If the target is a creature, it must succeed on a DC 19 Dexterity saving throw or take 65 (15d8) 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.

    

6. Death Ray. The targeted creature must succeed on a DC 19 Dexterity saving throw or take 75 (15d10) necrotic damage. The target dies if the ray reduces it to 0 hit points.

    

7. Fire Ray. The targeted creature must succeed on a DC 19 Dexterity saving throw or take 35 (8D8) fire damage. 

8. Banishing Ray. The targeted creature must succeed on a DC19 Charisma saving throw or be banished to his home plane for 1 minute. If the creature is already in his home plane , it is banished to a harmless plane of existance.
9. Mind Ray. The targeted creature must succeed on a DC19 Intelligence saving throw. On a failed the creature takes 15 Psychic damage and his Intelligence and Charisma scores become .The creature can't cast spells, activate magic items, understand language, or communicate in any intelligible way. The creature can, however, identify its friends, follow them, and even protect them. At the end of every 30 days, the creature can repeat its saving throw against this spell. If it succeeds on its saving throw, the spell ends. A greater restoration, heal or a wish spell can all end this spell.
10. Reduction Ray. The targeted creature must sicced on a DC19 Constitution saving throw. On a fail the target's size is halved in all dimensions, and its weight is reduced to one-eighth of normal. This reduction decreases its size by one category--from Medium to Small, for example. Until the spell ends, the target also has disadvantage on Strength checks and Strength saving throws. The target's weapons also shrink to match its new size. While these weapons are reduced, the target's attacks with them deal 1d4 less damage (this can't reduce the damage below 1).

The Behydra can take 5 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 Behydra regains spent legendary actions at the start of its turn.

Eye Ray. The Behydra uses one random eye ray.

Tail. Melee Weapon Attack: +15 to hit, reach 25 ft., one target. Hit: 28 (4d8 + 10) piercing damage.

Tail. Melee Weapon Attack: +15 to hit, reach 25 ft., one target. Hit: 28 (4d8 + 10) piercing damage.

Bite. Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 21 (3d10 + 6) piercing damage. When bitten by the BeHydra the creature takes an additional 5 poison damage.

Move. The BeHydra can move up to its speed.