Originally posted by: marvdmartian
Looks as though it's an anchor and screw all in one, where you insert it into the hole, and when you tighten the screw, it spreads the anchor wings. The sort of thing that you'd use where you don't have easy access to the back side of the material you're attaching something to. Might be designed as a one time use item, that would need to be drilled out and replaced every time.
Are they made of plastic? Looks like it, from the picture. If so, and if you have access to replacements (or something else you can substitute), I'd drill them out and replace them.