Big Steely
From the Super Mario Wiki
Bowser drops a Big Steely during the final battle of Super Mario World.
Big Steelies are large invincible balls that Bowser drops from his Koopa Clown Car in Super Mario World. Mario can Spin Jump to avoid getting crushed by them.
It is unknown how Bowser fits Big Steelies in his Clown Copter.
A similar item appears in Super Mario 64.
[edit] Appearances in Other Media
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.
