Battery Dragon

Breeding
You can get this dragon by breeding an Electric Dragon with a Metal Dragon at the Breeding Mountain or Ultra Breeding Tree.

Breeding an Electric Dragon with a Metal Dragon may also result in a Gold Dragon.

Damage Calculator
To explain, when attacking with Electric, Battery deals double damage against Fire and Metal, half damage against Dark, and no damage against Earth or Electric. When attacking with Metal, Battery deals double damage against Earth and Ice, half damage against Fire and Metal, and no damage against Electric. When defending, Battery takes double damage from Water and Plant, half damage from Ice and takes no damage from Electric or Metal.