Here's a quick, fun story from my childhood: My brother and cousin once decided to start throwing CDs at each other, having a big ol' CD fight around my uncle's house. With the laws of physics working together in perfect harmony, my brother flung a CD at my cousin, who just entered a different room and was closing the door behind him. The airborne disc tilted so it fit vertically through the crack in the door, made it through, and sliced my cousin's cheek. It wasn't a serious injury, thankfully, and the story proves that while digital, non-physical forms of media are on the rise, CDs still have great potential as weaponry.
His creation works a lot like those battery-powered foam disc shooters we had growing up, but, you know, beefed up. Instead of batteries, this contraption is powered by a Harbor Freight angle grinder, and the mechanism for feeding the CDs into the firing chamber, again, is a lot like foam disc shooters. The CDs sit on a stack, and an actuator pushes a thin blade that looks like a hockey stick. This blade pushes the bottom-most CD into a position where it can be grabbed be the grinder's wheel and flung pretty dang fast.
The original video is above, but JZSlenker also decided to make a follow-up clip that explains how his device works. It's a fun piece of creative design, so check it out above and below.
Featured image: JZSlenker