What happens next? When items are dragged to this folder they'll be almost immediately spit back out to the desktop. Hilarity ensues.
To undo what you've done: Delete the folder. If the real hard drive used to appear on the desktop, open Finder's preferences, choose General, and enable the Hard Disks option.
This should go without saying, but I'll say it anyway: When pranking family members or co-workers in these ways, be sure that you're nearby and ready to undo your work. Additionally, to avoid an unwanted poke in the snoot, be very careful about who you select as your victim. Choose unwisely and the April fool may be you.
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