In a move surely intended to channel its namesake, a Hellcat on a dyno lit itself on fire. Luckily, the whole situation was resolved without injury and uploaded to YouTube for your viewing pleasure.
To be clear, it doesn’t seem to be the car’s fault. As you can see in the video, a strap holding the car down broke on the run. As the uploader notes in his Reddit thread, once the strap wasn’t holding it back the car’s rear end want to come around sideways.
Since the dyno keeps the car tracking straight, the car flexes under its own twisting force. In this case, the wheel and brake rotor appear to have slid sideways and come into contact with the brake pad. This is known as side loading the brakes and can lead to some spectacular failures.
In this case, you can see that failure happens very quickly after the car breaks free from its straps. The left rear brake immediately side loads, generating a lot of heat that has to go somewhere. It starts whipping out sparks before the whole brake rotor is burning and the pads are glowing.
Someone standing by is able to get a fire extinguisher on the pad as the car rolls to a stop and no one was injured, but it goes to show just how much damage even a dyno run can do it something goes wrong.