If you see someone on Facebook encouraging you to "tell Siri 108"—don't do it.

Siri does all sorts of neat things if you know all the easter eggs, but the latest prank on Facebook is one that you want to steer clear of unless you're in a real emergency situation.

You may have already seen people posting for all their followers to say "Hey Siri, 108" to enable 3-way FaceTime, or promise that you'll be sure to get a laugh. The truth is, by saying "Hey Siri, 108" it's actually a shortcut for Siri to call emergency services for you.

Mic

Now, for someone in a real emergency situation, this is a great tool.

Luckily, there is a five second window for you to either cancel the call, or continue through to 911. You definitely want to cancel. Not only because it's juvenile, but you could potentially be eating up resources for someone who is actually in need of medical service.

It's a prank call when someone calls 9-1-1 for a joke, or calls 9-1-1 and hangs up. Prank calls not only waste time and money, but can also be dangerous. If 9-1-1 lines or call takers are busy with prank calls, someone with a real emergency may not be able to get the help they need. In most places, it's against the law to make prank 9-1-1 calls.

So avoid the cops, and that feeling when you realize you've been pranked on the internet.