Google Doodles are the various modifications or humorous features the company does to its logo that appears on its home page to mark holidays, birthdays of famous people, and major events.
The doodle that depicted a picture of a UFO sucking up one of Google's Os with a tractor beam was linked to the search 'unexplained phenomenon'.
It sparked widespread confusion and speculation online since there seemed to be no major event at the time.
Claims including that it was a sign the Earth had made contact with aliens emerged. Some also believed it was a publicity stunt for new sci-fi film District 9, while others thought it was the anniversary of the Voyager I spacecraft.
According to the Telegraph, Google did little to clear up the mist, saying in a statement, " We are actively looking into the mysterious tweet that has appeared on the Google twitter stream and the disappearance of the 'o' on the Google home page. We hope to have an update in the coming weeks."
And now, it has been revealed that the doodle was in honour of Zero Wing, a 1980s Japanese video game, celebrating its 20th anniversary.
Google was said to have resorted to the classic example of 'gamer humour' for Zero Wing's birthday.