The Big Box of Bad is one of Romeo's major inventions. Its intended purpose was to cover The City in a blue-green colored grid and to place many flags with Romeo's face on it across the area, thus renaming the city either "Romeoville" or "Romeopolis". Towards the end of "Gekko and the Mayhem at the Museum", a giant sphere (intended to be a booby-trap to stop the PJ Masks from interrupting the construction of the device) was dropped on the device, disabling the previously mentioned grid and rendering it useless.
The device itself was constructed inside the Museum with Robot's help. The device consists of many plates which resemble motherboards, and several lightbulbs.