What does a silverfish bug look like?

It is a skinny long bug. It has about 4 legs on each side that are bent in about a ninty degree angle. They are NAST!

Three legs each side - they are wingless insects with elongated, silvery-grey bodies.

Whether they are pests or not I would not like to say. As for "NAST[Y]" - probably not. They might eat certain garden plants, perhaps.