Mystery USB is a custom microcontroller board designed to plug directly into any standard USB-A receptacle for power. The compact board integrates a small OLED display, a push button, an indicator LED, and a buzzer.

Each device contains a game composed of three sequential challenges with increasing difficulty: speed, reflexes, and patience. While the first two can be solved quickly, the final challenge requires several hours of dedicated focus. From the moment it powers on, the screen hints that clearing all three stages unlocks a tangible reward.

Units were sealed inside durable capsules and hidden in public spots around Paris and beyond. Short drop videos posted on social media sparked spontaneous scavenger hunts as followers rushed to locate them. Beating the game displayed a unique secret code to claim a prize by mail.

Field Notes
Every hidden capsule was tracked down and retrieved by the community. While many attempted the challenges, only a determined few managed to beat the final stage and claim their reward.