Clockwork Dragon

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

Immutable Form. The Dragon is immune to any spell or effect that would alter its form.

Magic Resistance. The golem has advantage on saving throws against spells and other magical effects.

Multiattack. The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 17 (2d10 + 6) piercing damage.

Claw. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 13 (2d6 + 6) slashing damage.

Tail. Melee Weapon Attack: +11 to hit, reach 15 ft., one target. Hit: 15 (2d8 + 6) bludgeoning damage.

Frightful Presence. Each creature of the dragon's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 16 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the dragon's Frightful Presence for the next 24 hours.

Breath Weapons (Recharge 5–6). The dragon uses one of the following breath weapons.

Elemental BreathWeapon (Recharge 5–6). The dragon uses one of the following breath weapons. The type of attack depends on the crystal cylinder in place:

• Acid Breath. The dragon exhales acid in a 60-­foot line that is 5 feet wide. Each creature in that line must make a DC 18 Dexterity saving throw, taking 54 (12d8) acid damage on a failed save, or half as much damage on a successful one.

• Lightning Breath. The dragon exhales lightning in a 90-­foot line that is 5 feet wide. Each creature in that line must make a DC 18 Dexterity saving throw, taking 54 (12d8) lightning damage on a failed save, or half as much damage on a successful one.

• Fire Breath. The dragon exhales fire in a 60-foot line that is 5 feet wide. Each creature in that line must make a DC 18 Dexterity saving throw, taking 54 (12d8) fire damage on a failed save, or half as much damage on a successful one.

• Cold Breath. The dragon exhales an icy blast in a 60-foot cone. Each creature in that area must make a DC 18 Constitution saving throw, taking 54 (12d8) cold damage on a failed save, or half as much damage on a successful one.

• Poison Breath. The dragon exhales poisonous gas in a 60-foot cone. Each creature in that area must make a DC 18 Constitution saving throw, taking 54 (12d8) poison damage on a failed save, or half as much damage on a successful one.

• Repulsion Breath. The dragon exhales repulsion energy in a 30-foot cone. Each creature in that area must succeed on a DC 18 Strength saving throw. On a failed save, the creature is pushed 60 feet away from the dragon.

• Slowing Breath. The dragon exhales gas in a 60-foot cone. Each creature in that area must succeed on a DC 18 Constitution saving throw. On a failed save, the creature can't use reactions, its speed is halved, and it can't make more than one attack on its turn. In addition, the creature can use either an action or a bonus action on its turn, but not both. These effects last for 1 minute. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself with a successful save.

• Weakening Breath. The dragon exhales gas in a 60-foot cone. Each creature in that area must succeed on a DC 18 Strength saving throw or have disadvantage on Strength-based attack rolls, Strength checks, and Strength saving throws for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Shocking Scales. If a creature makes a melee attack against the Clockwork Dragon, the Dragon can use a reaction to deal lightning damage. The attacker must succeed on a DC 18 Dexterity saving throw or take 10 (4d4) lightning damage.

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

Detect. The dragon makes a Wisdom (Perception) check.

Tail Attack. The dragon makes a tail attack.

Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 10 feet of the dragon must succeed on a DC 19 Dexterity saving throw or take 13 (2d6 + 6) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.

Change Cylinder (Costs 2 Actions). The clockwork mechanics in the mouth and throat of the dragon rotate and rearrange to move a different cylinder to the back of its throat. Each cylinder is a different metal and some contain different crystals imbued with elemental power. The cylinder in place determines the type of breath weapon it can use:

• An Onyx in a copper cylinder: Acid
• A Saphire in a Bronze cylinder: Lightning
• A Ruby in a Gold and Brass cylinder: Fire
• A Diamond in a Silver cylinder: Cold
• A Bronze cylinder: Repulsion
• A Copper cylinder: Slowing
• A Gold cylinder: Weakening