It stays on with the help of an old back pack that we glued to the roof of the car. This car was a huge hit with kids and adults. We are already planning this years costume and its only July !
My son was 6 y.o. and about 4 ft tall. the car was about 18 inches wide 12 inches high (add 4 inches to the roof height) and about 4 feet long. We played the transformer theme song for him to "transform" to. It was time consuming but the end result was well worth it. "