Along with Water, Baton and Top, Iron appeared in Air-Ride-in-Style - Part II of the anime, and was created by fans. There was a contest in Japan for fans to submit their own Copy Ability ideas, and this was one of the winning entries.
Iron Kirby has two forms. His first has him wearing a golden bodysuit with a cobra-shaped crown and a cobra staff, giving him a rather Egyptian style. He can use the staff to deflect attacks. His main attack is transforming into his second form- a giant golden Kirby statue which rolls to crush enemies.
The sequence starts with Kirby glowing with energy, then he is covered in some iron and wields a staff, which he swings.