As the eBay description explains: "This log car was built by the special effects team at Universal Studios for use in the movie, 'Flintstones, Viva Rock Vegas'. It is a custom built chassis with an electric motor and electric disc brakes, much like a golf cart. It was all hand carved out of foam to look like wood. It was covered in resin for durability and hand painted... It cost about $50k to design and build... Just in time for Halloween!"
And don't feel too bad about missing out on your chance to own a piece of movie infamy history, the top bid was far short of the suspected reserve so it might pop up again in the future. And if a foam log isn't your idea of a classy ride, the seller is still offering Wayne's 1976 AMC Pacer, Chris Tucker's Corvette from Rush Hour, and the Grinch's sleigh from the live action feature starring Jim Carrey.
Quick quackout to DuckFat for the tip!