Totally guessing here!!!!
It's probably not really what I'm describing...but... there is a company named VMC that makes fishing tackle. They have a lure called a Darter Head that looks a bit similar, but I somewhat wonder if they ever made one of heavy ferrous metal. Does it look like it might have had a loop on the side of the fat, round piece, where fishing line could have been attached?
Again, I really can't fathom that they made an iron lure, but you never know.
It also reminds me of the spike on one of those old-style red, road flares.