If you thought Google I/O would be nothing but smartphones and complex code, you clearly weren't banking on Google diving head-first into virtual reality.
Sure, Google Cardboard has been around for a while, but it looks like chump change compared to Oculus Rift or HTC Vive. That's where Daydream comes in - it's a complete rethink of how VR works on your phone, from films to games.
It starts with Android N, which is getting overhauled with plenty of VR-specific tweaks, like faster screen response times, reduced latency and more accurate motion sensors for better head tracking.
Google's also thought about hardware, coming up with a set of recommended specs that smartphone makers will need to match to call their phones "Daydream-ready". The first handsets won't be turning up until later in the year, but Samsung, HTC, Huawei, LG, Asus, ZTE, and other manufacturers are all on board.
Don't think you'll be slapping these VR-friendly phones into a tatty old Cardboard headset, either.
Google's got a Daydream-ready reference headset design that you'll actually wear, rather than just hold up to your face. Your phone will still slot inside, but a comfortable head strap should keep it locked in place without making your arms cramp up.
It'll come bundled with a controller for playing games, too. It looks a lot like the Oculus controller, only it's got built-in motion controls like a Nintendo Wii remote. That's a big step up from simple head-tracking and tap-to-attack VR games that have turned up on Android to date.
Games should look better as well, with Android N supporting Vulkan GPU tech that ramps up the graphics without hammering your battery life or processor cycles.
Daydream is set to arrive in the Autumn, but developers will be able to start putting games and tech demos together as soon as Android N arrives.