Beholder Dragon

Legendary resistance(3/day) .  If the Beholder dragon fails a saving throw, it can  choose to succeed instead

Antimagic field. The beholder dragon has a 150 foot cone of an antimagic field that acts like the spell antimagic field . The beholder can hove the cone coming from them as a bonus action. 

Breath weapon(recharge 5-6). The Beholder dragon exhales the breath of its type. Each creature in a 30 foot cone takes 80(10d10 + 30) fire damage

Eye ray(recharge 4-6). The Beholder dragon shoots out 2 random of the following eye rays:

Paralyze ray: The Beholder dragon chooses a target within 50 feet of them. The target must make a  DC 18 Wisdom saving throw or become paralyzed until the next turn

Draining ray: The Beholder dragon chooses a target within 50 feet of them. They have to make a DC 18 Strength saving throw disadvantage on saving throws, attack rolls, and ability checks until the end of their next turn.

Damaging ray: The beholder dragon chooses a target within 50 feet of them. They must make a DC 18 Dexterity saving throw, or take 25(4d10 + 5)fire damage or half on a successful one.

Death ray: The beholder dragon chooses a target within 50 feet of them. They must make a DC 18 Constitution saving throw or 50(10d10) Necrotic damage. If this makes them drop to 0 hit points, they die.

Multiattack . The beholder dragon makes 2 claw attacks.

Claw. Melee Weapon Attack: +8 to hit, reach 5 ft., 1 target. Hit: 20 (3d10 +5) Slashing damage. 

Dragonic shield. When an attack hits the beholder dragon, the beholder dragon's AC increases by 3, and the person hitting them takes 5(1d10) fire damage

The Beholder dragon can take 3 legendary actions choosing from below. 

Claw attack. The beholder dragon makes a claw attack.

Eye ray(Costs 2 actions). The beholder dragon recharges its eye ray, then uses it.

Breath weapon(Costs 3 actions).  The beholder dragon recharges its breath weapon, then uses it. 

Enter the description for how mythic actions work for your monster here.

Mythic Action Name (Costs # Actions). Enter the description for your mythic action.