Saw these at the supermarket the other day:
This was something I've never seen before! They were sold next to the onions and the garlic, looked like slugs but were hard.
Very weird looking... veg??
Well, thanks to Google, I could find out that it's actually an aquatic plant that bear these fruits. Apparently you boil these and eat them as snack - Chinese Water Caltrop.
I'm not sure I want to try... they didn't look very appetizing to me...