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

Fire Absorption. Whenever the dragon dynamo is subjected to fire damage, it takes no damage and instead regains a number of hit points equal to the fire damage dealt.

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

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

Magic Weapons. The dragon's weapon attacks are magical.

Multiattack. The dragon makes two attacks: one with its bite and one with its claws.

Bite. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 19 (2d10 + 6) piercing damage.

Claw. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 13 (2d6 + 6) slashing damage.

Tail. Melee Weapon Attack: +12 to hit, reach 15 ft., one target. Hit: 15 (2d8 + 6) bludgeoning damage.

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

Molten Breath. The dragon exhales magmatic metal in a 20-foot line. Each creature in that area must make a DC 19 Dexterity saving throw, taking 33 (6d10) fire damage on a failed save, or half as much damage on a successful one. the magma lingers until the end of the dragon's next turn, dealing 3d10 fire damage to creatures that enter this space or end their turn within the line.

Oil Breath. The dragon exhales a lightning-blue oil in a 60-foot cone. Each creature in that area must succeed on a DC 19 Strength saving throw or fall prone. The oil lingers until ignited by an effect that would deal fire damage, then deals 2d8 fire damage to those within its area

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.

Heat Terrain. The dragon heats a 15 foot square of terrain to its melting point. This square is difficult terrain. When the terrain becomes heated, each creature within its area must make a DC 15 Dexterity saving throw. On a failed save, a creature takes 4d8 fire damage, or half as much damage on a successful save. A creature takes the same damage when it enters the square for the first time on a turn or ends its turn there.

Adapt (Costs 2 Actions). The dragon's inner mechanics trigger, sustaining it beyond what it normally can. Roll 1d8.