11-year-old Joseph DeRose decided he wanted to (cross) dress as Samus Aran for Halloween this year. So he and his dad set out to build a replica of Samus's Metroid Prime-era Varia Suit, starting with the arm cannon. The final cannon has a speaker and LED lights controlled by an Arduino microcontroller, so it can be made to fire simulated Power Beam, Plasma Beam and charged shots. Joseph even has to correctly "log in" to use it!
The rest of the costume is still incomplete, but at this point Joseph has a perfectly acceptable backup costume: "Guy With This Awesome Arm Cannon."