Developer Dong Nguyen has followed through with his threat to take down his mega-popular game, Flappy Bird, which is no longer available on the iTunes App Store or Google Play as of Sunday afternoon. Nguyen had previously said that he would take the game down over the weekend for reasons unknown. On Twitter, Nguyen, whose surprise hit is making $50,000 a day in ad revenue, said that he "cannot take this anymore" and would remove the game in 22 hours, or midday Sunday. He ruled out a couple of the most obvious potential explanations, saying that there were no legal problems (Nintendo corroborated as much), the game had not been acquired, and he had not quit making games.

The notoriously difficult Flappy Bird was created in mid-2013, but it only gained recognition over the past weeks as a sudden rise in popularity brought it to the top of both the iOS App Store and the Google Play Store. It's received both genuine and backhanded praise for its simple design, which asks players to simply navigate between pair after pair of pipes without hitting either one. Just a few days ago, Nguyen told The Verge that he was thinking about a sequel, so this is a sudden turn of events.

Update: This article has been updated to reflect that Flappy Birds was removed from Google Play and the iOS App Store on Sunday and that Nintendo denied sending any formal complaints about similarities to the game and the Mario series.