“Dunno if I’m out of the loop, but what the hell is this?” Crypt of the NecroDancer player RireMakar asked on Reddit last May. In the main folder of the game’s SteamApp root directory, the data-miner unearthed a cryptic sigil, an iris embedded in the palm of a hand, which he posted online. A few hours later, Josh R. (aka MachMatic), bored, decided to look at the image’s code with a hex editor. In it were indications of another buried image, which he extracted: a few curving lines broken up by circles, with the edges clipped off, signaling that the image was not alone. It was a puzzle piece.