UFO DOWN per chromethemer.com

The UFO Down extension; Creates a real-like UFO icon in your web browser after a few seconds of inactivity, that opens a pop-up link to play UFO Down, right in your browser.

UFO Down – is a game in which you need to shoot at the UFO with a variety of weapons and score as many points as possible without missing. It's a decent way of relieving some stress for a few minutes.

Access the game whenever you want to with this UFO themed extension.