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.