Open your Google search box and type ‘Zerg Rush’ and watch the ‘O’s destroying all your ‘Zerg Rush’ search results.
Zerg Rush is a common strategy where a player builds a many weak units as he can, then rushes the enemy base. Usually works best early in the game. Taken from Starcraft, where often zerglings (really cheap unit that can be built in large droves quickly) would be sent at the start of the game to kill everyone in the first couple moments.
You can also fight with the evil ‘O’s in this easter egg by clicking on them several times. You can also share your score on Google+. Once the animation finishes, you are rewarded with “G.G.”, which is the shorthand for ‘good game’.
Easter eggs are the hidden treats left by the Google coders to make searching a little fun. You can also try out other famous easter eggs like “Tilt,” “Askew”, “Do a Barrel Roll” or even the “Let it Snow.”