Be warned that the video (above), from YouTube user David Jenkins and his girlfriend, contains expletives, so you'll want to turn the volume down or don a pair of headphones if you're at work or near children.
A photo captured by Twitter user Jason Low (above) shows the 918 Spyder alight.
Witnesses who spoke to Global News claimed that petrol overflowed and then ignited from heat of the car's exhaust.
The fire occurred at a petrol station in the town of Caledon, which is around 40 minutes north-west of downtown Toronto.
A later series of photos from Twitter user David Perry (above and below) show the aftermath of the fire, with the rear of the 918 burnt and gutted, and the cabin filled with fire retardant.
CTV News has confirmed that the rare and expensive Porsche 918 Spyder belonged to the Michael Wekerle, one of the hosts of the Canadian version of reality TV show Dragons' Den. No-one was injured in the incident.
In statement to AutoGuide, Porsche Canada said, "Porsche is very concerned but cannot comment as we have no other source of information except these media reports at this time. We are first and foremost happy that apparently no injuries and other damage have resulted from the incident as reported. Porsche is prepared to bring its technical resources to help all authorities who are investigating the matter."
Only 918 copies of the 918 Spyder will be produced. The petrol-electric hybrid carries a list price of US$845,000 ($967,000) in the States. The drivetrain consists of 453kW 4.6-litre V8 behind the driver and passenger, and an electric motor on each axle. In total the car has 661kW of power at its disposal.
Earlier this year Porsche recalled the 911 GT3 after two vehicle fires in Europe.