Banana In the Tailpipe

You've got someone on your tail. Could be a cop, the local bully, or a very persistent Loan Shark. You could try to slow them down by shoving a banana (or a potato, or similar size-filling object) in the tailpipe or muffler of their car. That way, you could give yourself time to escape and have a good laugh at the victim's expense as their car sputters and churns and fails to go anywhere. If the script calls for it, the car might even explode.

If only it worked like that in real life. While a banana or a single potato jammed into the tailpipe will probably be ejected at high speed, completely blocking the tailpipe of a car with something that can't simply be blown out will smother the engine. It will not, however, set the car on fire.

A subtrope of Vehicular Sabotage.

Examples of Banana In the Tailpipe include:

Anime and Manga

There was an episode of the Little Lulu anime where Wilbur's butler was replaced by a stricter butler who anticipated all of the tricks that Lulu and the others were going to pull on him. Finally, they come up with a plan to work together to get rid of the mean butler. One of the tricks involved Tubby stuffing a handkerchief in the tailpipe of the limosine, and when the mean butler checked the tailpipe, the handkerchief came loose and he wound up with a face full of smoke and soot from the tailpipe.

Comic Books

Messed with in one of the early issues of the comic Spy Boy, where Bombshell stops a (moving) car of bad guys by tossing what appears to be a lit cigarette into the tailpipe. The car blows up several blocks later. Considering that Bombshell is an explosives expert, however, it's not quite as far-fetched.
Billy the Cat uses it too.

Film

The Trope Namer here is the film Beverly Hills Cop, where Eddie Murphy's character used this technique to foil a group of bumbling police officers. Famous for a notorious editing screwup: the banana he holds is curved, but the one in the tailpipe is straight - they couldn't fit the bent one in the tailpipe.
- Parodied in the "Trial of the Century" episode of Clerks the Animated Series. Judge Reinhold (the actor, acting as the courtroom judge) is lured away from Dante's trial by Axel Foley, who "needs (his) help!" - and they spend the evening stuffing bananas in people's tailpipes and watching them stall, but the fun ends when the local grocer reveals that he's run out of bananas. Then Judge Reinhold wakes up ("No! Axel! Come back!").
  - "I had that dream again!"
- Somewhere there is an interview with Terry Pratchett where he imagines the Discworld subversion of this: someone on stakeout on horseback, and someone else (the Librarian?) sneaking up behind them with a banana...
  - Something similar actually happens in Night Watch. Except instead of a horse it's an ox. And instead of a banana it's a handfull if fresh ginger. And instead of making the animal stop moving...
In the live-action version of 101 Dalmatians, raccoons put a large nut in the tailpipe of the bad guys' truck. The pressure does shoot the nut out eventually - when the bad guy is examining the tail pipe.
In the movie Hollywood Knights, the titular gang shoves a potato into the tailpipe of the squad car of two bumbling cops at the local drive-in diner... with hilariously loud results!

Live-Action TV

This happened in The Three Stooges a couple times.
Columbo did this with a potato.
A variation was used in Pushing Daisies: the murderer shoved a potato into the tailpipe of Ned's car to fill the car with exhaust and knock out Ned and Emerson during a stakeout.
- Such a thing could only happen if the exhaust system already had a leak up near the passenger compartment, which they would have noticed when the car suddenly became louder because the muffler was being bypassed.
- The same was used much earlier in an episode of Ironside.
Also subverted in Minder, in which a potato was used in this manner to shoot out and smash the window of another car.
This trope also occurred in an episode of Diagnosis: Murder, this time with a wad of cash.
When the MythBusters tried this, everything they stuffed up the tailpipe shot out immediately when Jamie started the engine.
Happened in Eastenders, with a potato. A man put it in his enemy's car's tailpipe and sniggered as the car sputtered. He stopped laughing when the pressure ejected the potato into his shop window.
In one episode of The Fresh Prince of Bel-Air, Will mentions that some students at his old school once keyed a teacher's car and stuck a potato in the tailpipe. His cousin Hilary hears this, and is later caught rubbing a potato on her rival's car and leaving her keys in the tailpipe.
Used in an episode of Psych to stop a car thief from reaching 200 mph in a stolen car and thus getting away with murder.
Averted in favour of the more realistic option in, of all things, Glee, when Mercedes stuffs tater tots up the exhaust pipe of Sue Sylvester's Le Car and does several thousand dollars' worth of damage.
Happened in Tee Off, Mr. Bean when the eponymous character hits a golf ball into a car's tailpipe, causing it to churn and sputter for several seconds before shooting the ball out at high speed.
MacGyver: In "A Prisoner of Conscience", Mac stalls the car of the secret police who are tailing him by sticking a potato in the exhaust pipe.
Miss Fisher's Murder Mysteries: In "Blood at the Wheel", Phryne sabotages Jack's car by stuffing her stocking into the exhaust pipe.

Radio

In the fictional town of Lake Wobegon (as heard on A Prairie Home Companion) everyone buys either Fords or Chevys, depending on religion. This is mandatory. In one case someone who bought foreign couldn't get his car started the next day 'cause someone had stuck a potato up the tailpipe.
In Tree From My Youth, Salsa is able to destroy a Pig Mask tank by shoving what is implied to be his own feces in the tailpipe.

Video Games

The second case of Apollo Justice: Ace Attorney featured a car being disabled by - wait for it - a pair of panties. MAGICAL panties..
- To the relief of one and all, the person who they were stolen from (yes, stolen from) doesn't wear them; they're part of a Bag of Holding-type act. But that doesn't make the choice of prop any less disturbing...
  - Earlier in the case, Klavier Gavin has trouble with his motorcycle; the tailpipe is clogged due to him using the wrong kind of oil. Naturally, this is important at the end.
In Space Quest 5: The Next Mutation, the hero, Roger Wilco, is being stalked by a gynoid that's out to kill him for alleged mail fraud. How does Roger Wilco save himself? By hiding in a log, then, when the gynoid lands on top of said log, sticking a banana-like fruit in the exhaust pipe of her jet pack, causing it to explode.
In the Spider-Man game for Playstation, you have to close several smokestacks with covers, to cause an effect "like a banana in a tailpipe". In the sillier What If? mode, the tops of the covers actually have bananas on them.
Not in the game itself, but in a Diddy Kong Racing promo video from Nintendo Power, at one point the host mentions someone stuffed a bag of acorns into the tailpipe of Krunch's plane, with Conker being the primary suspect.

Western Animation

In the Futurama episode "The Honking", Leela plans to kill the were-car by shoving a silver potato in its tailpipe. Unfortunately, it doesn't have one, "thanks to Ed Begley Jr.'s electric motor, the most evil propulsion system ever conceived!"
- Again in "Into the Wild Green Yonder" when the Feministas sabotage a sweeper by pouring sugar in the fuel tank and shoving an organic potato in the tailpipe.
In Arthur, the family car was disabled by a rattle (the toy) in the tailpipe. The family only figured it out after Arthur called Car Talk.
A clear Shout-Out in the super-short-lived Clerks the Animated Series: One episode revolved around spoofing courtroom dramas and featured actor Judge Reinhold as...well, an actual judge: the Honorable Judge Reinhold. The episode became a crazy patchwork of dream sequences, usually ending in a Catapult Nightmare for the character having the dream. In Reinhold's dream, his final verdict is interrupted by Detective Axel Foley, the lead character of the Beverly Hills Cop series, bursting into the courtroom and telling "Billy" he needed his help. (Judge Reinhold played Detective William Rosewood in the Beverly Hills Cop films) Reinhold eagerly drops his black robe and rushes to Axel's aid. The two spend many happy hours stuffing bananas in tailpipes and laughing as cars malfunction...until the fruit vendor runs out of bananas at which point it's Reinhold's turn to catapult awake.
In Where on Earth Is Carmen Sandiego?, Zack disables Carmen's flying machine by shooting an arrow into the exhaust port.
In the Family Guy episode "Viewer Mail No. 2 (Point of Stew)", Stewie attempts to stuff a Twinkie in Brian's tailpipe of his car only to have it shot back on his face and ends up on an unexpected ride with Brian.

Real Life

There have been advertisements in the past for locking caps that fit over tailpipes to disable them.
Try stretching an ordinary latex balloon across the pipe. Since it expands, it won't rocket off instantly, giving it time to smother the engine. Then, if you've done everything right, it will pop, making a loud noise and spooking your victim without actually causing damage to the car (aside from whatever damage you can cause by making the engine stall).

And stop snickering, already!!