From the Super Mario Wiki
The Cracker Launcher is an item that appears in Super Smash Bros. Brawl. After any players grab it, they will shoot it, upon pressing the attack button. The Cracker Launcher shoots fireworks that explode on contact with opponents or the ground. The players are able to walk and jump while holding the Cracker Launcher, and they can adjust the launcher's angle with the Control Stick ( for the horizontal Wii Remote control scheme).
The last shot of a Cracker Launcher will be colored more vividly, and have a longer steam trail, indicating that the item is out of ammo. To change direction, players would have to dash the opposite direction. Additionally, players can't do mid-air jumps, nor use their shields while holding this item. And despite its power, the item is very hard to hold on to; getting hit with even a weak attack will cause the player to drop it.
 Trophy Information from Super Smash Bros. Brawl