Grinder

Grinders are metal discs found only in fortresses of Super Mario World. There are two types of Grinders: those line-guided and those without. The line-guided Grinders travel along a dotted line while the non line-guided travel across the floor. Those blades are rather large and cannot be jumped on, although they can only be defeated by sliding into them (which creates a glitchy symbol). Mario or Luigi can, however, Spin Jump onto them, which results in a high bounce with no damage to either them or the Grinder.