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

Whenever the Drachimera takes 25 or more damage in a single turn, one of its heads dies. and it looses a breath weapon (roll 1d10 to determine loss). If the lost breath weapon is rolled on the Drachimera's turn, that attack automatically misses.

At the end of its turn, the Drachimera regrows each of its lost heads, regaining 10 hit points for each head lost as well as regaining functionality over each lost breath weapon.

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

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

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

Multiattack. The Drachimera can make five bite attacks or a Chromatic Breath.

Bite. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 10 (1d10 + 5) piercing damage.

Chromatic Breath. The Drachimera shoots three of the following breath weapons at random (reroll duplicates), choosing multiple targets it can see within 120 feet of it:

1 - Fire Breath. The Drachimera exhales fire in a 60-foot cone. Each creature in that area must make a DC 17 Dexterity saving throw, taking 24 (7d6) fire damage on a failed save, or half as much damage on a successful one.

2 - Acid Breath. The dragon exhales acid in a 90-foot line that is 10 feet wide. Each creature in that line must make a DC 17 Dexterity saving throw, taking 22 (5d8) acid damage on a failed save, or half as much damage on a successful one.

3 - Poison Breath. The dragon exhales poisonous gas in a 60-foot cone. Each creature in that area must make a DC 17 Constitution saving throw, taking 21 (6d6) poison damage on a failed save, or half as much damage on a successful one.

4 - Cold Breath. The dragon exhales an icy blast of hail in a 60-foot cone. Each creature in that area must make a DC 17 Constitution saving throw, taking 22 (5d8) cold damage on a failed save, or half as much damage on a successful one

5 - Lightning Breath. The dragon exhales lightning in a 90-­foot line that is 10 feet wide. Each creature in that line must make a DC 17 Dexterity saving throw, taking 22 (4d10) lightning damage on a failed save, or half as much damage on a successful one.

6 - Wave Breath. Each within 30 feet of the Drachimera must succeed on a DC17 Strength saving throw or take 22 (5d8) thunder damage and be knocked prone. A creature that succeeds on its saving throw takes half as much damage and isn’t knocked prone.

7 - Synaptic Breath. The Drachimera exhales a psionic miasma in a 90-foot cone. Each creature in that area must make a DC17 Intelligence saving throw. After a failed save, a target has muddled thoughts for 1 minute. During that time, it rolls a d6 and subtracts the number rolled from all its attack rolls and ability checks, as well as its Constitution saving throws to maintain concentration. The target can make an Intelligence saving throw at the end of each of its turns, ending the effect on itself on a success.

8 - Confusion Gaze. The Drachimera seizes the mind of one creature it can see and forces it to make a DC17 Intelligence saving throw. A creature automatically succeeds if it is immune to being frightened. On a failed save, the target loses the ability to distinguish friend from foe, regarding all creatures it can see as enemies and will attack the closest target determined by the DM. At the end of each of its turns, it can repeat the saving throw, ending the effect on itself on a success.

9 - Pestilence Breath. The Drachimera exhales a virulent disease in a 90-­foot line that is 10 feet wide. Each target in that area must make a DC17 Constitution saving throw. On a failed save, it takes 24 (7d6) necrotic damage, or half as much damage on a successful save. If the target fails the saving throw, its hit point maximum is reduced for 1 hour by an amount equal to the necrotic damage it took. Any effect that removes a disease allows a creature’s hit point maximum to return to normal before that time passes. If a target is immune to disease, it is immune to this breath attack's secondary effect.

10 - Disintegration Beam. The Drachimera blasts laser beam in a 120-foot line that is 5 feet wide. If the target is a creature, it must succeed on a DC 17 Dexterity saving throw or take 36 (8d8) 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.