Sounds like the beginning of a joke, but it's not.
It's about a truck hitting a moose, catching fire and setting off fireworks.

Confusing?
Well, the truck was hauling fireworks in Ontario, Canada, hit a moose along the way, somehow caught fire, and of course that set off the impromptu fireworks display.

The trucker driver and passenger are ok, but no word on how the moose fared.
Check out the video, complete with fireworks.