Not only are you going to need a Nerf gun to disassemble, but you are going to need a bunch of electronic parts, since we are taking the "brains" out of the blaster, and replacing them with a Trinket.
You will also need some tape, glue, diagonal cutters, soldering equipment, patience, and maybe some padding for the guy who is about to be your target!
I included the Adafruit ID numbers for the parts required. The quantity needed for the project may not exactly match the quantity of parts from Adafruit. For example, you only need 2 TIP120, but Adafruit sells them in a 3 pack.