The Mirthmobile first appears in Wayne's World, when Garth picks up Wayne from his parents' house near the beginning of the film. It is also the setting for the famous "Bohemian Rhapsody" scene. It is used by both Wayne and Garth frequently throughout the film, sometimes while carrying other passengers (including Phil, Cassandra and other friends of Wayne and Garth). Despite the car's small size, it often carries up to five people at a time (when fully loaded, the rear end of the car rides noticeably lower because of the added weight). Its final appearance in Wayne's World is when Wayne and Cassandra leave Cassandra's video shoot.
In Wayne's World 2, the Mirthmobile is once again used frequently by Wayne and Garth. Its last appearance is after crashing through a pane of glass and some crates containing chickens when Wayne is on his way to crash Cassandra's wedding. He spots a red Alfa Romeo convertible sitting unattended in the street, and abandons the Mirthmobile to drive away in the Alfa instead. (The Alfa later runs out of gas, and Wayne abandons it on the side of the road and completes his journey on foot.) Two alternate versions of the Mirthmobile are later seen in the alternate endings of the film (see the Variations section below).
The Mirthmobile originally had a cassette player, which was used to play a tape of Bohemian Rhapsody. The car was later fitted with a CD player mounted on top of the dash.
The vehicle is equipped with a licorice dispenser mounted on the ceiling, consisting of an inverted clear plastic dome filled with red rope licorice, which is dispensed through a small hole with a hinged blade for cutting pieces off.
In Wayne's World 2, in addition to the CD player and licorice dispenser, the Mirthmobile is seen to have a dispenser for disposable drinking cups (actually also visible in the original Wayne's World) attached to the dashboard on the passenger side. At one point, Garth uses a garden hose nozzle inside the car to fill his cup, although it is not clear where the other end of the hose goes or where the water comes from.
The Mirthmobile almost certainly has an automatic transmission, since we never see Garth or Wayne shift any gears or use a clutch pedal.
The front and rear wheels do not match. The front wheels are the original 1976 Pacer wheels, while the rear wheels appear to be from a later model Pacer.
Although the car has seat belts, they are never used on screen.
The vehicle is registered in the state of Illinois. Its license plate number is F3B 259.
The alternate endings of Wayne's World 2 include two other versions of the Mirthmobile. In the Thelma & Louise Ending, Wayne and Garth, dressed up as Thelma and Louise, are in a convertible version of the Mirthmobile, which they drive off the edge of a cliff. The convertible was a custom vehicle built for the movie, as AMC never mass-produced a convertible version of the Pacer.
In the Happy Ending, the band Aerosmith arrives at Waynestock in a stretched six-wheeled Mirthmobile limosine, which has a badge on the side that reads "Mirthlimo 1" as well as much larger flame decals and different front wheels. Like the convertible Pacer, the Mirthlimo was a one-of-a-kind custom vehicle. The Mirthlimo is 36 feet long. (The actual prop car still exists, although it has been repainted.)
During Aerosmith's performance, the Mirthlimo is seen pulling up repeatedly, carrying more bands who have come to perform at the concert. Although the prop car is obviously the same, it is not clear if it is meant to represent multiple Mirthlimos, or the same one being used again and again to transport different bands.