Big Steely

Big Steelies are enemies in Super Mario 64. They appear in Bob-omb Battlefield, Tall, Tall Mountain, Tiny-Huge Island, and the DS remake's Battle Fort. They are large cannon balls that usually roll down paths. When Mario gets hit by them, Mario gets a fair amount of knockback along with 2 hits.

The Big Dud
Main article: Big Dud

In Bob-omb Battlefield, 2 Big Steelies are rolling around at the bottom of the mountain. After Big Bob-omb is defeated, a third will appear. A Bob-omb Buddy states, "Thanks to you, Big Bob-omb is nothing more than a big dud now." In certain copies, a lone Big Steely can be found stationary at the base of the mountain. The player can speak with it, who reveals itself to be the Big Bob-omb, congratulating Mario again on his victory while lamenting his defeat.