
Hedgehog sea urchins live on the seabed of the Adriatic coastline in great abundance. Locally they are considered a great delicacy. They are easy to catch. All you need is a diving mask with a tube. Dive down to the sea floor and gather as many as you can into your net bag.
The one in the photo above is still alive (it didn't want to sit still for the picture!) and they are eaten while alive, with the top half containing the "eye" cut off (so it can't see what you are doing to it?).

This plateful is ready to be eaten. You either just lick the insides out or, if you're feeling slightly more refined, you scoop them out with a small piece of bread.