A developer named Gustave has managed to get Windows to run on a smartwatch that runs a closed-source Android implementation called Wear OS.
By unlocking the smartwatch's bootloader, Gustave implemented workarounds including adding UEFI and faking a kernel header to run Windows on the watch.
Although the project is considered to be ridiculous and not recommended, Gustave claims it is real and provides the necessary resources for others to try it out.
There are alternative open options for tinkering with smartwatches available for those interested.