The two door fastback coupe version of the Dodge Dart was renamed 'Beaver' in 1971, but when the Chrysler marketing department realized 'Beaver' is slang for something else, they renamed the car Demon. The name Demon stuck for a couple of years, 1971-1972, but outside forces demanded Chrysler change the name yet again, and in 1973 Chrysler renamed the car to Dodge Dart Sport. I think it's fair to say Chrysler had trouble naming this car.
Here's a Dodge dealership promotional video comparing the 1971 Dodge Demon to the 1971 Chevrolet Vega. It's odd to hear someone refer to a car as Demon.
