More throttle is applied than can be managed safely causing the rear of the quad to "swap" with the front making for great entertainment to all those that happen to be watching at the time.
A swappa will usually ride like this where there is someone watching although they have been known to crash with no one around.
Face plants are often the result.
I crashed my quad, it was radical.
He just landed that jump sideways and then face planted in the whoops