It looks like a thing used to hold ceramic roof tiles. (or whatever they were called). I found a ton of them once where an old house had been moved to another location.
Caveman is correct, but I see the similarity to a wick winder... They're usually all mangled when posted here, making it clear they've been used in a nail like fashion. This thread has a good description by PBK about them: http://www.treasurenet.com/forums/what/190664-copper-things.html