So you have the Booby Trap all set up. You got the bait linked to a bomb, a cage, or even catapults aiming cream pies at the intended target. Everything is going smoothly and no one expects a thing, until...
Wait, what is that idiot doing there? Hold on- BOOM!
As a general rule, Booby Traps are indirect weapons that are not very discriminating about who or what they go off on, making them very susceptible to Finagle's Law, as illustrated above. As a result, any would-be Trap Master runs the risk of the trap going off on someone or something other than the intended target, often someone they don't want getting crippled, killed, humiliated in front of everyone, or outright pissed. And if this unfortunate trap-ee happens to be some big dude or creature who happened to get in the way, they may want to start running.
Subtrope of Spanner in the Works. Sister trope to Self Offense, Bullying a Dragon and Pity the Kidnapper. See also Hoist by His Own Petard for one who gets caught by their own trap. May lead to Unintentionally Notorious Crime or Murder by Mistake if the trap is deadly.
Compare Accidental Kidnapping.
Those examples were made for someone else!
- In Zombie Land Saga, while the girls are spending a period of time on the mountains, set up a trap to catch an animal for food. However Sakura proceeds to walk straight into the pit and is left defenseless as the boar they were trying to capture looms towards her.
- Becomes a real Epic Fail in an episode of Pokémon when Team Rocket somehow get themselves caught in their own traps. How that happened, as well as how they later escape, is never explained.
- Button Man: Harry is pretty adept at making traps, setting various ones in the forest near his home turf to take out all the other Button Men who are after him. Unfortunately however, his best friend Wiley walks into one by mistake.
- The Fabulous Furry Freak Brothers are alarmed to hear the police can break into homes without knocking, so they booby trap the apartment with falling bowling balls, high-voltage wires - then they have Fat Freddy go to the store, telling him "Don't forget to be careful coming back in". He walks along repeating the mantra...then forgets what he was going to get. He rushes back in and, well...
- Garfield: The page image comes from this comic, where Jon falls for a trap Garfield set up for Santa Claus.
- Kings of Revolution: At the battle of Yokosuka, Lelouch hides JLF General Katase's death and rigs a tanker of liquid sakuradite as a bomb. He intended to not only destroy the Britannians but take out an assassin working for The Empire as well. Unfortunate for him, the Time-Space Administration Bureau was also after Katase. With Lelouch unable to disarm the bomb, the tanker blows up the entire TSAB battalion and fails to kill any of his intended targets.
- Antagonist Amos Slade from Disney's The Fox and the Hound sets out several snap-jaw traps in the game preserve to capture that pesky fox, Tod. However, in Amos' fervent pursuit of Tod, he bumbles into a huge bear. While backpedaling, Amos steps onto one of his own traps, which snaps on his ankle, and anchors him in place. It's up to his hound dog, Copper, to distract the bear, sparing Amos from a horrible mauling. But even Copper is no match for it. Tod leaps onto the bear's back and and barely survives falling down a waterfall with it. As Copper approaches the fox who just saved him despite everything, Amos shows up to shoot Tod. Copper steps between Tod and Amos' gun, and the hunter eventually relents and decides he and Copper go home. As Amos turns to leave, he is quite visibly limping painfully.
- In Monsters, Inc., Mike is threatened by Randall to return Boo to her room during lunch break. When Sulley hears of this, he refuses to let Boo go back to her room, knowing full well that Randall is planning something, so Mike goes inside the room and starts jumping on Boo's bed to prove that it isn't a trap. As it turns out, it actually is a trap, and Randall ends up capturing Mike instead.
- Laird set up a booby trap long ago in the castle dungeon in The Princess and the Pea. He tried to lead Rollo into it until Fearless set it off.
- Winnie-the-Pooh: Pooh and Piglet try to catch the "Backson" by covering a Pit Trap with a picnic blanket and an empty honey pot. Later, after other shenanigans, Pooh sees a honey pot in the middle of the forest and goes for it.
Piglet: [not surprised] Oh, Pooh. You went back for the honey, didn't you? But I told you it was empty.
Pooh: Yes, and I believed you, Piglet. But my tummy had to see for himself.
- The Rescuers Down Under: Played with; early in the film, Cody falls into a Pit Trap that McLeach made to capture animals. Naturally, the poacher is quite surprised to find out he captured a boy instead of an animal, and (unsuccesfully) tries to hide the fact he's a poacher by blaming his pet goanna Joanna for having dug the hole. Then McLeach realizes that Cody knows the location of the rare giant eagle Marahute, and concludes he caught something he wants after all. Thus, he reveals his true colors and kidnaps the boy.
- Spaceballs: At one point, the villains believe they've captured Lone Starr, Barf, Vespa, and Dot, only to learn they've mistakenly captured their stunt doubles.
- Chitty Chitty Bang Bang: The two Vulgarian spies try to trap Caractacus Potts driving Chitty with his children and Truly Scrumptious, but instead, they trap Truly's father, Lord Scrumptious's car.
- Beetle in the Anthill: Kammerer and Sikorsky stakeout at the museum of alien cultures, expecting Abalkin to sneak in at night to examine the Detonators. However, to their surprise, they catch Dr. Bromberg instead — the leader of a faction opposed to Sikorsky, who reveals to Kammerer just why Sikorsky is after Abalkin (note that his "break-in" in the museum doesn't even constitute a crime, since he has an official permission to access its stands at any time).
- A children's book called Cat Traps shows a cat setting up various traps to catch something for food. Out of sheer coincidence, they end up catching something else: a bug instead of a mouse, a dog instead of a frog, a duck instead of a fish, etc. In the end, the cat gets food by begging his owner.
- The Thrawn Trilogy: Invoked when Thrawn wants to capture Luke Skywalker, despite C'baoth insisting Luke be left to him. Thrawn arranges to yank Luke out of hyperspace with an Interdictor cruiser, having his flagship there to make the capture attempt and an empty, expendable freighter nearby. The goal is to make it appear to Luke (and C'baoth) as though he was unfortunate enough to fall into an Imperial ambush meant for someone else, not him.
- Warrior Cats: Tigerclaw asks Bluestar to meet him on the road hoping so he could get her hit by a car there and kill her, but she is too sick to come and Cinderpaw ends up meeting Tigerclaw and getting hit by a car instead.
- The Twits: Every wednesday, the Twits eat Bird Pie. So the night before, Mr. Twit sets a bird trap by coating the branches of the big dead tree in their yard with hugtight glue. Any birds unfortunate enough to spend the night in the tree get stuck and thus end up used for the bird pie. One time however, a group of young boys decided to climb the tree and got glued to the branches instead, scaring away any birds. When Mr. Twit found them the next day, he was so enraged he actually considered to use the boys to make pie instead. Fortunatey, they realized in time they could get free by slipping out of their pants, since only those were stuck.
- Bassie & Adriaan:
- De Geheimzinnige Opdracht; in the Belgium episode, thanks to the Tracking Device hidden inside a Walkman the crooks send to Bassie a few episodes earlier, De Baron and Handige Harry think the two protagonists are on their way to them, and set up a booby trap involving one of Harry's homemade bombs. Too late do they find out that the signal is actually from their fellow crook B100 (who found the walkman after Bassie lost it), and they fail to warn him before he triggers the bomb. Good thing for B100 that Non-Fatal Explosions are in effect in this show.
- In the first 3 episodes of the next series, De Reis vol Verrassingen, the Baron, inspired by the events from De Geheimzinnige Opdracht, decides to set another trap for Bassie & Adriaan. He sends them a Forged Message supposedly from the same guy who send the two protagonists on all their assignments in Opdracht to trick the two into finding a hidden package on Curacao. This package contains another bomb. Unfortunately, Vlugge Japie, another old adversary of Bassie & Adriaan who used to work for the Baron, is also on Curacao. Naturally, he hears about this package, assumes it contains something valuable, and sets out to get it before Bassie & Adriaan do. He succeeds, thus triggering the bomb and saving the two protagonists (again, he survives thanks to Non-Fatal Explosions).
- In the Dad's Army episode "Operations Kilt", the Walmington Platoon are taking part in a training exercise in which they must prevent a rival platoon from capturing their headquarters, and decide to use a series of Tarzan-inspired mantraps to catch them as they advance through the woods. When they fail to catch the platoon leader Captain Ogilvie, Corporal Jones offers to go out and attempt to lure him into the last trap, but owing to some confusion and poor timing ends up caught in the trap himself.
- During the Memetic Mutation-tastic song "We Are #1" from Lazytown, Robbie Rotten has this happen with several traps due to the incompetence of his trainees as he tries to catch Sporticus.
- On True Detective, Marty and Rust discover a meth lab booby trapped with grenades. One of the cookers runs and gets blown to bits by them.
- In Danganronpa V3: Killing Harmony, Kaede sets up a complex trap to kill the mastermind, which ends up killing Rantaro when he goes to the library.
- In the epilogue of King's Quest (2015), Gwendolyn sets a trap for one of the yarblesnoofs she's hoping to catch. Instead, she ends up trapping another girl, around her own age. The hilariously unimpressed appearance of the prey must be seen to be appreciated.
- Bob's Burgers: In "Christmas in the Car", the Belcher kids lay out a "Santa trap" hidden in the fridge, but only end up catching Teddy.
- Happens three times in the classic Ducktales 1987 episode "Dinosaur Ducks". Huey Dewey & Louie try and capture a baby dino but their traps only succeed in capturing a saber tooth tiger, a T Rex and themselves.
- Ed, Edd n Eddy: In "From Here to Ed", the Eds lay a trap for Kevin by laying syrup in the street for him to get stuck in while riding his bike. Of course, it's Jimmy who gets stuck.
- Looney Tunes: In Stop! Look! And Hasten!, Wile E. Coyote sets up a Burmese tiger trap to catch the Road Runner with. Instead, he catches... a Burmese tiger. Somehow.
- In the My Little Pony: Friendship Is Magic episode "The Best Night Ever", Fluttershy, who wants to pet one of the animals at Princess Celestia's private zoo, sets a box trap with a carrot inside. After hearing a whistling sound she assumed to be a songbird, she triggers a trap, and it's revealed to be the gardener.
- Recess: Parodied in one episode when King Bob tries to prank the "Prankster Prince" who is TJ. Every time he sets up a trap, Gus happens to trip it instead. Every time.
- Just about every Scooby-Doo cartoon has Scooby and Shaggy end up caught in the trap Fred set to catch the Monster of the Week, which ends up caught by different means.
- The New Adventures of Winnie the Pooh:
- In one episode, Pooh sets up a box trap to catch a missing hammer. He instead catches a saw.
- In another episode, Rabbit, Tigger, and Owl try to cure Piglet's hiccups by setting a trap and using a cake as bait. They end up catching Eeyore instead.
Eeyore: If you didn't want me to eat the cake, why did you leave it lying around?
Tigger: Hey, how 'bout that? Them hiccufflings look a lot like Eeyores.
- In A Wild Hare, Elmer Fudd tries to catch Bugs Bunny with a Box-and-Stick Trap. He catches a skunk instead, but it takes him a while to find that out.
- Happens in Star Wars Rebels when a Star Destroyer tries to tractor The Ghost, but Hera jumps to hyperspace, and the tractors grab her pursuer. Too bad for the tractor officer, said pursuer was Darth Vader.
- The Loud House: In the Christmas Episode Eleven Louds A Leapin, Lana sets up various reindeer traps, but only manages to trap Luan (who, for good measure, was wearing a hairband with reindeer antlers).
- Every now and then, you would see examples of this on videos or the news. The news reports usually Played for Drama where unexploded hidden bombs (i.e. landmines and claymores) and terrorist IEDs get civilian bystanders instead of enemy soldiers or other intended targets. Videos of the trope on social media tend to be more Played for Laughs.