A mysterious five-second video causes phones to slow down and eventually crash. The video is a seemingly harmless mp4 file showing what appears to be a very quick magic trick.
Phones are reported to continue working fine for up to 5 to 10 seconds before then slowing down and eventually crashing.
It's not entirely clear why the video has such an effect but it's thought the file is corrupted or possibly encoded with a malicious bug. Luckily, there doesn't appear to be any long-lasting effects and the bug can be fixed with a hard reset. This is done by pressing and holding the power button and volume down button simultaneously for iPhone 7, or the power and home button for all other iPhones.