The Yellow Shell appears in Super Smash Flash 2 as a throwing item that can be used by both picking up the Shell and throwing it, or by jumping on it. It virtually works the same as the Green Shell as it keeps moving in one direction unless it hits a wall and then bounces in the opposite direction. Its quirk, though, is that it buries any grounded player that comes in contact with it, even the player who had thrown it, dealing 17% of damage. The Yellow Shell has a weakness and is that it is unable to damage any airborne opponent, the Shell simply ignores any collision.
Yellow Shells originate from Super Mario World, where they are worn by yellow Koopa Troopas. As with the other shells in the game, both Mario and Luigi can pick a kick the Yellow Shell to make it slide across the floor to take out several enemies. Its special quality, though, is seen when Yoshi has a Yellow Shell on his mouth, this makes him incredibly heavy to the point that wherever he lands, the ground trembles, rising puffs of smoke that flips out enemies. The qualities from the Yellow Shell in SSF2 is indirectly based on this, which implies that the shell is so heavy that it buries opponents that collide with it. The Yellow shell is the most scarce of all shell variants and it rarely makes an appearance in other Mario games following Super Mario World. Though unrelated, the Yellow Shell resembles the Gold Shell from Super Mario Galaxy, New Super Mario Bros. 2, and the Mario Kart Arcade GP series.