The Revealers, manufactured in 1992 and distributed in 1993, were a series of cars with a lottery type of game included. They were the original Mystery cars. The cars were sold in different clear blister packs, but they were wrapped inside a yellow opaque paper baggie. The baggie was intended to be dissolved in water, but it was easier and less messy to just tear them open. 

Though the identity of the car inside may appear to be a mystery, the numbers on the wrapping paper correspond with a specific model. Example; the "9" on the package suggests that inside is the Porsche 930. There are three color variations, though which color variation is unknown until you reveal it!