The guy at the store called these "elephant nails". Charming. But that's really what they look like, pre-frying.
I'd only tried these ready-made, sometimes in Chinese or Indian restaurants, and I think I bought a bag a few years ago in Holland. This was the first time I fried them myself though, and though the flavor is much the same, it's a lot of fun. The little hard shards will expand to the fluffy chips you see in the picture. And they're mighty tasty, too!
I got my bag at FineFood, but I'm sure you can find them in many Chinese or Asian supermarkets, too. Or apparently you can make them from scratch.