Piping /dev/urandom into the USB HID keyboard stream[1] of a Windows 11 host logon screen makes for some funny videos.
Semi-related, you can do silly things with the "Microsoft OS Descriptor" USB parameters (properties get mapped to registry keys/values), but it looks generally safe, since not much happens automatically with those properties, especially outside of the Explorer view for Mass Storage/MTP/PTP devices.
1. Pi Zero W 2 in OTG mode, setup as a composite device via ConfigFS, and literally mashing random bytes into /dev/hidg0