Spiny
Spinies are the spiky-shelled enemies thrown by Lakitu. In the Super Smash Bros. series, Spinies always appear in their 8-bit forms. They cannot be killed by jumping on them, as this damages/kills Mario.
In Super Smash Bros. Melee
An 8-bit Spiny walks around in the background of Mushroom Kingdom, and can be seen on Yoshi's Island.
In Super Smash Bros. Brawl
In SSBB, they behave like they did in Super Mario Bros. - walking back and forth and damaging all players who touch them. They can be devastating, but are slow and easy to avoid. They appear in their original sprite form as part of the effect of the Assist Trophy character, Lakitu. If they are dropped on top of a character, that character will be meteor smashed. If Lakitu is KO'd, the spinies still stay alive, walking around until they all fall off the screen.