It looks like a particular type of fishing hook that I have seen. The flattened out part is the shank. The one I saw had a snailed knot that was secured onto the shank, below the flat area. And then the knot was tightened up. The flattened out part keeps the knot from slipping off. The ones that I saw didn’t have a barb either, and much smaller, the tip must have gotten bent into that curl somehow.