The Ectomobile, was in the first draft of Aykroyd's script, and he and John Daveikis developed some early concepts for the car. Dane developed fully detailed drawings for the interior and exterior and supervised the transformation of the 1959 Cadillac Miller-Meteor ambulance conversion into the Ectomobile. According to Aykroyd, the actual vehicle was "an ambulance that we converted to a hearse and then converted to an ambulance." Early concepts featured a black car with purple and white strobe lights giving it a supernatural glow, but this idea was scrapped after cinematographer László Kovács noted that dark paint would not film well at night. It also had fantastic features such as the ability to dematerialize and travel inter-dimensionally. Two vehicles were purchased, one for the pre-modification scenes. Dane designed its high-tech roof array with objects including a directional antenna, an air-conditioning unit, storage boxes and a radome. Because of its size, the roof rack was shipped to Manhattan on an airplane, while the car was transported to the East Coast by train. Sound designer Richard Beggs created the distinctive siren from a recording of a leopard snarl, cut and played backward.