Devil Nut- Or how to Trapa bicornis Halloween style

In honor of all hallows eve here is the Trapa bicornis, bat nut, devil pod etc...

You can mostly find them in Asian markets. They taste a bit like chestnuts and should be cooked the same way, by a Dickensian urchin with a runny nose and light fingers.
They grow like this.

Looks pretty vulgar doesn't it? They're invasive and weedy in the American South and Australia so don't Jonny Appleseed them. But feel free to roast and munch them if you want to get at the Devil's nuts. Or hang them around your neck like the Afar men used to do to their enemies. Yes. Nut necklaces.