The Key is an item in Super Smash Bros. Brawl. It only appears in the Subspace Emissary. A Key is used to u

nlock nearby doors. They break easily on higher difficulties. Enemies, fire, and traps will stop you, so you must be careful when carrying a key. Keys are glowing objects that shine similar to the shines of a Stock Ball, so they are easy to notice. However they are small but bigger than Screw Attacks and Franklin Badges. Keys can be used for throwing, however, if you use them like that you'd have to go back to where you found it.