It took drawing these things for me to finally find out what they were. This is part of a collection of fish decoys my mother owned and passed on to me. These decoys are used in ice fishing. A large hole is cut in the ice and these decoys are lowered into the water and moved about in a fish-like manner (or turtle-like, or dragonfly-like manner depending on the decoy being used) to attract fish near the surface where they are then speared with a really big 10 prong spear. Pretty wild, eh?
Sketching is an education.