An event in northern Mexico turned tragic on Saturday when a monster truck driver lost control and drove into the CROWD, killing at least eight people including four kids.

There's footage of it online that was shot from the other size of the arena, so you don't actually see too much.

Several witnesses said they saw the driver hit his head on something inside the truck right before it happened.  And in the video, it sounds like the gas pedal might have gotten stuck.

But police are also testing the driver's blood to see if he'd been drinking beforehand.

WARNING:  This video includes disturbing content.