"Oregon manroot" is a wild cucumber with a perennial vine. The shocker is that it has a giant underground tuber that can be bigger than a basketball!
It has a lot of saponins in the root making it not so edible, but Native Americans used to grate it up and throw it in the water to temporarily stop fish from breathing for more convenient harvest at the surface.
I think you can harvest the seeds, but I haven't tried..
https://en.wikipedia.org/wiki/Marah_oreganus#Seeds_and_germination