Earlier this year, our video production team began spitballing ideas for a Halloween costume project. They likely thought the Ars editorial crew would suggest some boilerplate pop-culture "nerd" ideas, revolving around famous sci-fi or horror characters. Instead, they sighed after reviewing our long, technically challenging list full of stuff like robotic suits and diabolical person-sized packet-sniffing devices. (It was a stab at putting the "trick" into "trick or treat.")

In the end, we settled on a project that leans a little closer to the traditional affordable, last-minute costume ideas you'd find on the Web, though with a decent DIY tech-geek bent: your own see-through flesh wound.

The above video spells out the concept's design and execution at the skilled hands of costume designer Lowri Best. It begins and ends with little more than a tablet, a nylon strap, a sewing kit, and a small webcam. How much more you need to buy depends on how bonkers you want to go with your version. Maybe you just need the right cords to get your smart device to interface with the webcam. (We opted for an old Samsung Galaxy tablet, since we want to use a free Android app—USB Camera Pro, in our case—to interface with an external webcam.) Or perhaps you'll want to up the fleshiness of the wound by mixing silicone and a ridiculous amount of fake blood (which is what Best did, to great effect). Either way, the effectiveness of the effect mostly boils down to having your smart device's screen and back-facing webcam aligned reasonably well. If someone waves their arm behind you and it can be seen "through" your chest, you're solid.

Our test in Times Square was perfect to show off the costume's effectiveness, considering how bright that part of town is. (Fun fact: we originally tried gathering public reactions in Union Square, but the native New Yorkers filling Union Square didn't even blink—seen one girl with a giant hole in her chest, seen 'em all, I guess. The tourist crowd at Times Square, on the other hand, was everything we were hoping for.)

If you do build this costume, you'll want to play with the screen's brightness as you move between indoors and outdoors—but don't be too concerned about people complaining about its realism or not-quite-right perspective. After all, you made a home-built gaping chest wound. The people complaining probably made a last-minute "Eleven from Stranger Things" outfit. Who wins? You win.

Update: as several commenters are pointing out below, this is definitely not the first time this idea has been done—we even featured a Wired UK interview with a costumer creator who'd done something similar several years ago.