Trouble Magnet Gambit

" Kuan: Badger badger badger, badger badger badger, badger badger... Sid: AAAUUGH!! Stop it!! *hands Kuan paper* Okay, look, try this variation on the theme, same tune, different words. Kuan: Sure! *examines paper* Let's see now... Ahem Hastur, Hastur, Hastur-"

- User Friendly

This is the act of giving someone an item that is harmless on its own, but is intended to attract some external peril later on. For example, raw meat in bear country, or an air horn in snow-capped mountains.

Related to The Uriah Gambit. See also Chekhov's Gun.

Comics

 * An issue of Catwoman has Selina get hit in the face with one of the Joker's pies. The pie itself isn't harmless... but it does carry a radioactive tracer that draws two ballistic missiles right to it. Which means Catwoman has to race the missiles over the roofs of Gotham in hopes that the missiles don't catch up with her while she's in a residential area.

Film

 * In Never Say Never Again, Fatima Blush attaches a homing signal to James Bond's scuba tank so her radio-controlled sharks will attack him.
 * In X 2 X Men United, Mystique puts a syringe filled with iron in solution into an off-duty guard's butt. How bad this would be for him in the long term is unknown considering that he seems only a little bit under the weather the next day but he's also hung over and recovering from some kind of drug. But long-term effects don't really matter because Magneto uses the extra iron in the guard's blood to escape, killing the guard and that's definitely fatal.

Literature

 * In the Dragaera novel Jhereg, Keira uses her pickpocketing skills to replace Mellar's regular daggers with Morganti daggers (which destroy the victim's soul). Aliera then picked a fight with him and got stabbed, causing Mellar to panic and flee Morrolan's castle, allowing Vlad to kill him. Mellar didnt know that Aliera's soul was protected by her sword, allowing her to be resurrected.
 * In Children of Dune, the Atreides twins are sent elaborate robes by the rival Imperial House. The catch is two Laza tigers have been trained to attack and kill anyone wearing said robes.
 * Sherlock Holmes - Happens by accident in The Hound Of The Baskervilles, in which the escaped convict Seldon is secretly given some old clothes of Sir Henry's. The titular hound is set on the trail by the smell of Sir Henry's boot, and understandably mistakes Seldon for its real target because of the clothes' odor.

Live Action TV

 * In the Doctor Who story The Keys of Marinus, Vasor, in order to ensure that Ian does not come back from rescuing Altos, slips him some raw meat to attract the wolves.
 * In the 1970s The Bionic Woman episode "Deadly Music", an enemy agent attaches a homing signal to Jamie Sommers so trained sharks will attack her. And yes, this was probably the inspiration for the Never Say Never Again example above.
 * Star Trek: The Next Generation - A variation occurs on the episode where Picard is forced to take a vacation on the Pleasure Planet Risa. Riker raves about Risa at various points in the series and ask Picard to pick him up something called a "horga'hn" while there. Turns out the horga'hn is a fertility statue and displaying one in public (as Picard does, unaware of it's meaning) is essentially broadcasting that one is looking for some action, specifically a sexual rite known as jamaharon. When Picard finally got someone to explain why random women kept brazenly approaching/propositioning him as he tried to find a moment's quiet, he was NOT amused.

Video Games

 * Metal Gear
 * In Metal Gear, shortly before fighting the first boss, Snake is captured and his inventory stolen. When he retrieves his items, a savvy player will note that a transmitter has been placed in among his gear. As long as he carries it, guards are alerted to his presence.
 * Ocelot in Metal Gear Solid just cuts out the middleman, and gives him a bomb.
 * In Metal Gear Solid 3: Snake Eater, a transmitter is placed on Snake after his capture. If you don't remove it, you have to evade the Ocelot unit once you get back to the jungle, but you also get a bonus cutscene a little bit later.
 * In Left 4 Dead the Boomer has low HP and deals poor damage on its own, but it can vomit on survivors, attracting common infected to them.
 * In BlazBlue Arakune's projectile attacks work by having him "curse" the target, causing them to be attacked by insects (when he commands it) until they manage to land another blow on him.
 * Inverted in Dragon Quest III with the Golden Claw. Dangerous in the pyramid (every step's a random encounter, and you can't use magic in the basement where you get it), but once you leave, as long as you don't return to the pyramid, it's the fighter's best weapon.
 * StarCraft - In one of the most horrifically inhumane tactics in the campaign, Mengsk has Kerrigan plant Psi-Emitters on a rebellious planet's surface. This attracts the Zerg swarm to ravage the area. Actually a double example, as the Zerg then attract the Protoss fleet to simply incinerate the entire planet.
 * And again, with Edmund Duke at Tarsonis. "Who authorized the use of Psi-emitters!?"

Western Animation

 * South Park - Timmy tries to off Jimmy by giving him a parka identical to Kenny's. Jimmy then walks down the street with half a dozen fatal accidents just missing him.

Web Comics

 * In one User Friendly strip, Kuan is driving Sid crazy with the Badger Song, so Sid gives him a Lovecraft-themed version with "Hastur" for "Badger". Sic transit Kuan.

Web Original

 * This is used to kill a man in Whateley Universe. A man who is known to be rather friendly with the local weres is slipped a fungus that affects them like catnip does cats by a man who wants all the land he owns.