Utter the words -- and we don't suggest you do -- "charge my phone 100 per cent" to Siri, and your iPhone will try and call emergency services, after a five-second grace period in which you can cancel it. But why?
It might be a bug. Or, as The Verge suggests, it could be a feature that allows you to secretly call the police if you're in trouble. It seems unlikely, but stranger things have happened (like a woman getting in touch with Pizza Hut to save her from a knife attack). So far Apple is yet to confirm why it's a thing. Any ideas?
Oh and again: Don't try this. Calling the cops without good reason is a dumb idea.