The OPP in eastern Ontario are searching for a "17-wheeler."
It was an 18-wheeler semi-trailer truck, until one of its wheels came off as it travelled down Highway 401 near Morrisburg shortly after 5p.m. on Tuesday.
The errant tire struck four other vehicles on the highway - luckily, there were only minor injuries.
Police aren't sure that the driver realized he had lost a wheel.
Investigators are asking anyone who may know the owner of the truck to call them.