What happens when you mix water and grease? Exploding fireballs, apparently. At least that's what Gav and Dan, better known as "The Slo Mo Guys," found out when they demonstrated why you shouldn't use water to put out an oil fire.
Slowed down to 2,500 frames per second, the video gets REALLY hot -- fast. Here's a sped-up gif of the fire:
As The Slo Mo Guys explain in the video, the reason the fireball occurs is because "the water sinks through the oil, evaporates immediately on the surface of the pan throws all of the oil upwards in a big flaming, hot, melty mess." Yikes!
In order to actually extinguish an oil (or grease) fire, make sure to use baking soda to put out the flames instead of water.