Complex sentence: The other residents of Radiator Springs watch as Mater drives around frantically with the "Ghostlight" on his tail, before Mater tires himself out and the cars tell him it was all a prank to pay him back for all his pranks he played on them.
Split into simpler sentences: The other residents of Radiator Springs watch as Mater drives around frantically with the "Ghostlight" on his tail, before Mater tires himself out and discovers the truth. The cars tell him it was all a prank to pay him back for all his pranks he played on them.