This has been YouTube's biggest mystery for months: Weird videos - 80,000 of them - of red and blue blocks backed by odd electronic noises. What could they be?
Well, they weren't secret messages sent between spies, or beacons for extraterrestrial intelligences. They were merely tests.
The Webdriver Torso account started uploading videos to YouTube eight months ago at a pretty staggering rate -- as often as every two minutes at its peak. Every single one of them is 11 seconds long. Almost all of them are the same format.
One man went to great lengths to dig into the mystery, and came out the other end with a video that mocked the mystery - and provided the answer, with a Rickrolling video.
Turns out, YouTube was using the spontaneously-generated videos to test their uploading capabilities - and then the thing got out of hand.
Google, which owns YouTube, responded with a comment that folded in with the joke:
"We're never gonna give you uploading that's slow or loses video quality, and we're never gonna let you down by playing YouTube in poor video quality. That's why we're always running tests like Webdriver Torso."
Rickrolling is an old Internet trick that sends people to a video of "Never Gonna Give You Up" by Rick Astley. We thought it was a meme that had run its course - apparently not!