Google, like many companies, engages in a practice known as dogfooding. That's when a company has employees internally test new features and products before rolling them out to the public. While poking around in the recent YouTube APK, we found a little surprise. There's a GIF presumably shown in dogfood versions of the app to remind people to keep their big fat mouths shut.
Nyan Cat is no match for the dogfood... um, cat? I mean, it looks like a cat, but wouldn't a dog have made more sense for a dogfood GIF? At any rate, I suspect this GIF (in addition to being hilarious) is an implicit threat directed at testers. "Leak this stuff and you will be incinerated with lasers fired from Larry Page's eyes." The Larry Page bit is totally a guess, but I think it's a good one.