A rare, classic luxury car became completely submerged when it rolled into a lagoon Sunday just after winning best-of-class at a car show.

The owner of the 1938 Packard 1605 Super Eight convertible sedan apparently forgot to apply the parking brake, according to Autoweek. Bystanders tried to stop the vintage vehicle from rolling backward but the nearly 4,000-pound vehicle was too heavy, according to the Island Packet.

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A diver and tow truck company worked to pull the car from the murky depths of the water hazard on the Port Royal Golf Club golf course, according to the Island Packet.

The car won in the American Classics 1925-1948 category at the Hilton Head Island Motoring Festival and Concours d'Elegance. The 10-day event has become one of the country's best car shows, according to Autoweek.

"This was most unfortunate," Carolyn Vanagel, festival president, told the Island Packet. "We feel badly for the owners, whose car had just won best-of-class."

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