Iron ball

Big Steelies (also referred to as "bowling balls" in Mario Mania Player's Guide) are large iron balls that appear in Super Mario World in the last battle with Bowser. He drops these from his Koopa Clown Car. Mario can jump over them to avoid getting hit. Mario can also spin jump on them without getting hurt. It can be destroyed if Mario uses his sliding cape attack against it using a Cape Feather but it will show a glitched sprite.

In the Super Mario World episode "Send in the Clown", Bowser attempts to defeat Mario in one scene by dropping a Big Steely on him, which Mario dodges.

Bowser, with the same method, is shown dropping a Big Steely after Yoshi hits him with his Mechakoopas. Mario, however, uses a golf club and knocks the Big Steely at him.

Big Steelies graphics exist unused in the Super Mario Bros. game style object graphics in Super Mario Maker.