Tandem Parasite

Daisy, daisy, give me your answer do...

A tandem bicycle is that type of two-seat bikes with two sets of pedals that aging liberal couples and teenagers in Public Service Announcements ride everywhere. It works on the principle "2>1", according to which, it's easier to ride if there are two people doing the riding.

But, not all is good, because, as always, evil rears its ugly head in the form of a Tandem Parasite. This Complete Monster is the one in the back seat, whose parasitism is not visible to the hard-working, all-American front-seater. The rear-seater doesn't ride, but rather crosses his leg and smiles as the poor soul in front of him does twice the work he should be doing - the idea here is that the rear-seater is mockingly taking advantage of the rider.

It should be noted that, sometimes, the parasite has some reason not to ride, like being distracted, or having been hurt, if you buy those cheap excuses.

A Dead Horse Trope, or even a Dead Unicorn Trope.

For some reason, this was considered funny many years ago. Now, not so much.

Examples of Tandem Parasite include:

Anime & Manga

Team Rocket on Pokémon uses a lot of pedal-powered vehicles. About half the times they use one, Jessie sits back and lets James and Meowth do all the work, which occasionally leads to disaster.

Comic Books

Superman, Batman and Robin in a World's Finest comic. Robin was riding.
Jughead and Archie did it. Archie was riding.

Literature

Robert Fulghum wrote a piece on this. A New Age couple riding a tandem bicycle. The guy in front thinks he's in control 'cause he decides where they're going. The gal in back knows she's in control 'cause she can stop pedalling and look around every so often. A nice essay on gender roles.
Happens, of course, in Jerome K. Jerome's book Three Men on the Bummel (aka Three Men on Wheels), the sequel to Three Men in a Boat.

Live Action TV

The Goodies Trandem is a three-man variation. The original version was an ordinary (sic) tandem with an extra seat at the back. Tim and Graeme pedalled, Bill being shortest was at the back in the non-pedalling seat. Later on the BBC prop department actually built a version with three sets of pedals.
Variation with the Chucklemobile from Chucklevision, where the two brothers supposedly pedal side by side but Paul never bothers, even though Barry can see him not doing it.

Video Games

This happens quite easily in Wii Sports Resort's Cycling game if one of the riders doesn't know what they're doing or refuses to keep rhythm.

Western Animation

Burns and Smithers on The Simpsons. It Got Worse when Smithers got stung by a bee and begs Burns to get him to a hospital. How does Monty do it? By ordering Smithers to do it, of course.
Brian and Lois on Family Guy
Kif and Amy in the Futurama episode "Three Hundred Big Boys". The twist is that it's a flying bicycle, and the pedals power the wings. In this case, Amy is just easily distracted (waving to some friends on the ground below) and wasn't trying to be rude.
- Bender and his two clones in "Benderama", only all three are leaning back. The bike promptly falls over.
Mr Herriman does it to Bloo in the Foster's Home for Imaginary Friends episode "Let Your Hare Down" when Bloo is attempting to teach him how to have fun and Herriman isn't having a bar of it.
In the Tex Avery version of Goldilocks and The Three Bears, Papa and Mama bear are the parasites, leaving poor Baby bear to do all the pedaling.
In the Looney Tunes short "The Dover Boys", Tom Dover is riding a tandem bike all by himself, with Dora Standpipe leaning on the front, which is left up in the air due to Tom being The Big Guy.