The .11 Whatzit is a wildcat cartridge (of sorts), created by opening up a shotgun primer to accept a single #6 Birdshot projectile (which is .11 caliber). The primer itself, becomes the the cartridge.
This is mainly a novelty, and it doesn't appear that any gun has actually been made to chamber and fire this "cartridge". That is, if it can even be considered a cartridge, depending on personal opinion. It has a primer, because it is a primer, as well as a projectile. But of course, it lacks any powder. However, it should theoretically be possible to chamber and fire this round, since gun barrels appear to be available in as small as .10 caliber.