Courage Shell

A Courage Shell is an item found in Paper Mario: The Thousand-Year Door. Using one can boost Mario's or his partner's Defense by 3 points for two turns.

Interestingly, the name "Courage Shell" applied earlier to a piece of armor available to Bowser in Super Mario RPG: Legend of the Seven Stars. In this game, the Courage Shell could be bought in Monstro Town and was one of many "shell" armors that Bowser could buy and wear.