Not the first time I've seen a car on fire and the driver didn't know it. The last time was at a bracket race and it was the car in the left lane beside me. As I'm slowing in the shutdown, he goes FLYING past me (which had me wondering "Where's he going?" LOL). Turns out it was because he was sliding in his own transmission fluid while trying to stop, which he barely managed to do before he'd went off the track. After stopping, he just sat there like the driver in the video, not knowing there was a fire underneath.
The fire was caused by the same thing that had him sliding. Rubber lines going to his trans cooler, which were spraying onto his headers.