The five second clip appears to have been discovered by reddit users yesterday. Once played on your iPhone, the device will start to become unresponsive after about 10 seconds and eventually lock up entirely. The home button and power button stop working and only a hard reset will bring your device back.
The Verge says it has tested the bug on multiple iPhones running the latest iOS 10.1 updates, and beta copies of iOS 10.2. We'd advise against playing an unknown videos until Apple has issued a software update to address the problem.
Take a look at the video below for a demonstration. Please follow iClarified on Twitter, Facebook, Google+, or RSS for updates.