Help! It's the hook / spring thing!!

Well, I've spent the day cleaning a sewing machine, an old Singer 9420, and when I began to replace the bobbin case, I noticed a lot of fuzzies in this old machine. Anyway, long story short, this thing popped out, which kinda looks like a deformed fish hook. Does anyone know where it goes? I was pretty sure that I found it near one of the two screws just near what looks like a black bar (that's the slider bar that holds the cover which protects the bobbin case.

If anyone knows, I'd sure be grateful for some advice. I'd love to get this machine going for my mother. Thanks!