Armadillo Dragon

Breeding
You can't breed this dragon directly with an earth dragon and a metal dragon because it will not work. You can breed a star dragon with a battery dragon to get this. you can also get it and cool fire by breeding Medieval (Metal + Fire) and Snowflake (Ice + Earth).

Below are a few different breeding combinations.

Metal Dragon + Paladin Dragon (This combination will give almost 100% of possibility.)

Star Dragon + Battery Dragon

Medieval Dragon + Snowflake Dragon

Medieval Dragon + Alpine Dragon

Jade Dragon + Star Dragon

Paladin Dragon + Robot Dragon

Medieval Dragon + Mud Dragon

Platinum Dragon + Earth Dragon

Medieval Dragon + Earth Dragon

Training Center
He is actually listed with two attacks the same, this is not a mistake.

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

Deep analysis
Counters : Fluorescent Dragon, Zombie Dragon, Medieval dragon, etc