Saw this a while back, was wondering if it ever got into production. It was invented by that slingshot guy. Has 8 arrows, each time you cock it rotate and fire the next arrow, so you can get quick follow-up without having to load an arrow each time like other airgun arrow.
http://youtube.com/watch?v=d83IOGGEDWA
http://youtube.com/watch?v=d83IOGGEDWA