Does anyone know what this outlet is for and why it would be sparking with nothing in it.
It's a NEMA 15-50 receptacle. 50A, 125/250V (two hots, neutral, and ground). The style of box and receptacle are typical of North America, so then it's just a matter of comparing its shape to a list of NEMA configurations, such as the one here: https://www.generatorjoe.net/html/web/outlet/quailplug.html
NEMA standard connectors are the most common style of mains power connectors used throughout North America. Nearly every receptacle installed in a North American building will be a NEMA type, except for some very specialized connectors such as used for wet locations or special equipment.
This sort of connector in particular is commonly used for high-power devices, most commonly things like ovens and clothes dryers.
If it's sparking all on its own, then it's contaminated with some sort of conductive residue or possibly has a loose wire inside.