it's got a hard, prickly shell that is inedible.
Inside, it's kinda like a walnut in that there are hard things that you aren't supposed to eat.
The fruit is the round nuggets inside between the stuff you aren't supposed to eat.
Durian has a funny odor that many people don't like, and the fruit is pretty unique in flavor.
give it a shot. I've never bought a frozen one before, let us know how you dislike it. (i'm saying dislike because the odor and taste will be unlike anything you've had before, and 9 times out of 10, that means you wont' like it)