Gruntoks, an artist in the Netherlands, modified two Nerf guns with pony themes. At the top is a Nerf-N-Strike Maverick revolver decorated with the colors and cutie mark of Rainbow Dash. Below that is a Nerf N-Strike Barrel Break. It's made to resemble Pinkie Pie's party cannon, a device made to launch party supplies on demand.
Bonus item: Gruntoks also makes armor, usually from leather and chain mail. His ponies go into battle with suitable protection. Here's Pinkie Pie's suit made with iron M6 rings.