Koopa Troopa

Koopa Troopa is a common recurring enemy coming from the Mario series.

In Super Smash Flash
The Koopas appear in the first stage of the Adventure Mode called Super Mario World along Winged Goombas but unlike the Mario games, its shell cannot be used as a weapon as one hit destroys the whole Koopa.

In Super Smash Flash 2
Koopas once again appear. They, like the previous game appear in the Adventure Mode stage, Mushroom Kingdom. It is most likely the shells can be used as weapons in SSF2 it was said in the SSF2 Dojo.