We're used to seeing high-performance sports cars and supercars being reduced to mangled wrecks as a result of excessive speed and a lack of experience. In this case, however, the driver simply forgot to apply the parking brake, with disastrous consequences.

As reported by Express & Star, the driver of this BMW M4 Convertible parked up in front of a marina but left the car in drive. To their horror as they got out of the car, the BMW M4 rolled down the embankment, crashed through some railings, and plunged into the marina for an impromptu swim.

Unfortunately, while the M4 Convertible is a technically advanced sports car, it doesn't have amphibious capabilities, so it didn't take long before it became fully submerged underwater. That's over $77,000 down the drain.

Staff at the marina site put anti-pollution measures into place around the car to stop fuel from leaking further. Luckily no one was injured in the incident, but the BMW M4 Convertible will most likely be totaled as water entering the engine bay would have caused terminal damage to the car's 425-hp 3.0-liter turbocharged six-cylinder engine. Before it took a dip into the water, this BMW M4 Convertible would have been capable of hitting 0-62 mph in 4.2 seconds.

Since the car will probably be a total loss, the unfortunate owner may want to invest in the all-new 2021 BMW M4. Set to debut in mid-September, the all-new BMW M4 will boast a significant performance boost and improved handling over its predecessor.

BMW recently confirmed the new M3 and M4 will be powered by a 3.0-liter twin-turbo straight-six engine producing 480 hp in the base models and 510 hp in the range-topping Competition spec. Power will be sent to the rear wheels through a six-speed manual in the base version, while the range-topping Competition will come with an eight-speed automatic transmission and be offered with all-wheel drive at a later date.