Highlighting a gap in Valve’s moderation of Steam, there is a game on the Steam Store that installs an empty folder on your computer. While it is likely an error on the developer’s part it appears there is nothing in place to prevent it happening.
Shadow: Treachery Cannot Be Tolerated is on sale for £1.69. It’s described by its developer, Riad Arifin, as the first part in an episodic first-person shooter story, in which “You will be attacked by few goons and you have to kill them all before they kill you.”
If you try and run the game after installing it you’ll be met with this message: