Created by "Outof Darts"https://www.youtube.com/watch?v=0BSfB9OWdcE
Basically a Nerf Rival Zeus modified to be fed by a backpack containing a coil tube/hopper assembly pressurized by a blower. Demonstrated capacity is 270 rounds, theoretical max capacity is 330 rounds.
The chief disadvantage is that it's noisy as hell (Outof Darts says you will sound like a leaf blower), but with that much ammo and firepower, just one person in a squad could make that squad practically invincible during a mission. A whole squad of people with these weapons would, barring mistakes, be invincible.
It is pretty amazing. I have never seen a blaster like this.