Green Shell

The Green Shell is a throwing item that appears in Super Smash Flash and Super Smash Flash 2. It keeps moving in one direction unless it hits a wall and then bounces in the opposite direction. It is an item from the Super Mario Bros. series and has appeared in all of the Super Smash Bros. games, where it has similar properties as it does in Super Smash Flash 2.

In Super Smash Flash
In Super Smash Flash, Green Shell it's a item for throw , common to TKO's in Enemy Characters. It's a common item

In Super Smash Flash 2
In Super Smash Flash 2, it appear as a throwing item that can be used by both picking up the Shell and throwing it, or by jumping on it. It hurts all players, including the one who used it. It deals 11% of damage and has a moderate knockback. It is one of three koopa shells.
 * The Design of Koopa Shell comes from Super Mario Advance 2 : Super Mario World