A random hard drive has appeared on the desktop

EtreCheck is a FREE simple little diagnostic tool to display the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to help people help you with your Mac. It will not display any personal info.

https://www.etrecheck.com/

Thanks for Old Toad’s etrecheck instructions…

https://discussions.apple.com/thread/255121100?answerId=259529290022#259529290022

Use the Note tool on the bottom of this editor's toolbar, as shown in the image, to copy and paste the output from EtreCheck. In a Reply before you click post, look for this to add longer texts...

How do you know it is a hard drive and noisome other file or app? Have you tried opening it to see what's inside? You could right-click on it to see what get info says about it. Finally, try restarting the computer in the Safe Mode. That fixes a lot of things. Press the Shift key on restart. The repair process takes several minutes while the OS repairs itself and empties its caches. Then restart normally and see what happens.

Aha, thanks for the report!

I had a cat that would rename drives or files when I wasn't looking!

Any DVDs, USB sticks or Camera Cards involved?