Hot Metal Dragon

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

Breeding a Fire Dragon with an Electric Dragon may also result in a Laser Dragon.

9 times out of 10 it will result in Laser Dragon

Battle
To explain, when attacking with Fire attacks, Hot Metal deals double damage against Water and Ice, half damage against Earth and Fire and no damage against Metal. When attacking with Electric attacks, Hot Metal deals double damage against Fire and Metal, half damage against Dark and no damage against Earth or Electric. When defending, Hot Metal takes quadruple damage from Water, half damage from Fire, and takes no damage from Plant, Electric or Metal.