Mr. Rental is a device located aboard Spaceball 1. It is an area where ship personnel can access video cassettes.
In the Movie
After Lone Starr and his group crash landed on the Moon of Vega, Dark Helmet and Colonel Sandurz were struggling to locate them on Spaceball 1's scanners. Suddenly, Sandurz had a bright idea to find the whereabouts of Lone Starr and Vespa; to watch the video cassette of Spaceballs: the Movie, and wait for a scene to appear that may reveal their location. Helmet is confused on the idea, bringing up the point that a Spaceballs cassette tape cant possibly exist, since they were still in the middle of making the movie, but Sandurz tells him about a recent breakthrough in home video marketing: instant cassettes that are out in stores before the movie is finished. While Helmet is skeptical of the idea, a corporal sifts through the various films in Mr. Rental until he finds the instant cassette of Spaceballs: the Movie. using the cassette, the Spaceballs are able to discover the heroes' location on the Moon of Vega.