The programmers at Google offer a little homage to Blizzard's strategy title.
Google famously allows its workers to spend one fifth of the work week furthering whatever project sparks their interest. Quintessential Google features like the Transit directions in Maps, or cultural documentation like the Google Art Project all started through work using this "extra" time. I can only imagine that the latest Easter Egg found in Google's search engine came from a 20% project, but this time it's a nod to a little game from Blizzard called StarCraft.
Here's how you find it: Go to Google. Type "zerg rush" into the search and hit enter. Watch as the "zerg Os" rush to your search results and start attacking. Health bars go down until the result items are destroyed, that is, unless you start clicking on the zerg Os to fend them off.
There's even a scoring mechanism that tracks APMs (actions per minute) and how many zergs you kill before the page is blank. Given the endless rush of zerg Os, there's no way to avoid a GG, but you can fight the good fight nontheless.
The whole thing just seems like a nod to Blizzard's Starcraft where the rush of tiny bugs is a staple strategy for the insectoid race of Zergs. But then you notice the built-in way to post your score to Google+, and the subtle integration might be a ploy to draw mroe traffic to Google's struggling social network.
Ah, who cares? It's still fun. Can you beat my high score of 54 zerglings with 176 APM?