Not to be confused with the Red Shell.

The Red Koopa Shell is a special item in SSBB, which can only be obtained by attacking a Red Koopa Paratroopa or Red Koopa Troopa. Although similar (but not identical) in appearance to a Red Shell, it behaves more like a Green Shell, and does fire damage. Also, if left alone for a while, it will turn into a Red Koopa Troopa.