Just Whistle

""If you ever need my help again, just blow this whistle!""

A trope most common and easy to recognize in old-school Western Animation, but fairly universal and even Older Than Print. Basically, it describes a scenario like this: Bob rescues Alice from some horrid peril. In gratitude, Alice gives Bob a little whistle and tells him something along the lines of, "If you ever need my help again, just blow this whistle!" After that, whenever Bob needs some rescuing for himself, he'll pull out that trusty whistle, and poof, like magic, Alice will be there to lend a hand. In more complex cases it may require (explicitly or implicitly) a Magically-Binding Contract.

Compare Call on Me, wherein the whistle is not included.

Anime and Manga
"Kasuga: I thought you were supposed to appear when I blew into it. Sasuke: Well, that's obviously impossible. But hey, I'm here now!"
 * This happens in One Piece. When the Straw Hats arrive in the Sky, Gan Fall saves them from Wiper, and gives them a whistle, telling them to blow it if they need him. Later, when being attacked by one of the Priests, Chopper does just that, and it turns out to be a subversion because Gan Fall loses to the priest, and he and Chopper are only saved by some old fashioned Deus Ex Machina.
 * Sengoku Basara plays with this one. Finding Kasuga determined to go on a one woman Roaring Rampage of Revenge against Oda Nobunaga, Sasuke gives her a whistle and tells her to blow it when she's in trouble. When she finds herself cornered, she blows it... and it turns into a rocket powered glider.


 * This seems to be how Minato's Hiraishin kunai work in Naruto. He can teleport to the location of any of the kunai, and he's more or less the most badass ninja ever to exist (discounting legends), so his allies can use them as basically infallible one-hit-kill weapons. He's a few times given them to allies just in case they're ever in sufficient danger to need it.
 * Defied in Daily Lives of High School Boys. While Rubber (band) Shooter did give a bullied, younger Hidenori a whistle and told Hidenori to call him with the whistle when Hidenori needs help, when Hidenori actually got bullied and attempted to use the whistle, he appeared and asked Hidenori not to rely on the strong to always help him. Note this example of defiance made Rubber Shooter Hidenori's role model.

Comic Books

 * In Silver Age Superman comics, Jimmy Olsen had a special wristwatch that produced sound ("zee-zee-zee!") on a high-pitched frequency that only Superman could hear, summoning him to the rescue. This was revived on the Paul Dini animated series.
 * Subverted in a Superman mini-series where Superboy gave a friend a whistle to call him in case he got in trouble. Unfortunately, when the guy is trapped in a fire and frantically whistling for Superboy, the superhero is attending to a major disaster, is forced to stay to help the dozens of people in danger, and cannot get to his friend until it is too late.
 * The Bat-Signal.

Film

 * In The Santa Clause, an elf gives Santa Claus' son a magical snow globe early in the film; at the end, he tells the kid that if he ever wants to see his father, he just has to shake the snow globe and it will summon his father.
 * Family Man has its Magical Negro angel/genie/whatever (played by Don Cheadle) give Jack a bike bell with no explanation when they first meet; later, when it becomes clear that the guy was some kind of supernatural being who has enacted an It's A Wonderful Life-style universe-rearrangement, Jack is seen walking around ringing the bell like a lunatic, assuming it was one of these. The only effect is that his wife thinks he's insane (well, insaner), and when his daughter appropriates the bell for her actual bike (which is implied to be the actual reason the angel gave it to him, since he was also planning to rearrange the universe such that Jack would have a daughter who'd be receiving a bike on Christmas morning) Jack gets hilariously upset. "That's MINE! She took my bell!"
 * In "The Little Vampire" Anna gives Tony a good luck charm (dead mouse), and tells him to whistle if he ever needs her help. He later does so when Rookery shuts him in a coffin, and Anna, as promised, shows up to let him out.
 * A non-verbal variant appears in Who Framed Roger Rabbit?. Benny the Cab tells Eddie that "if you should ever need a ride, just stick out your thumb." Later, just when the weasels are closing in on him and Jessica, Eddie sticks out his thumb off-handedly (to point which direction to run off to) and Benny instantly drives up to pick them up.
 * In Jack Frost the son is given a harmonica the dad claims is magical and will always get him to his son. After he dies he brings him back from the dead to be with his son.
 * In Bedazzled, the Devil gives Stanley seven wishes, giving him the ability to terminate a wish and return to wherever he himself was at the time by blowing a raspberry. Since the Devil throws a nasty twist into each wish, Stanley goes "Phbtbtbtbt!" quite a lot, until, with a wish turning him into a nun (not what he wanted) it inexplicably doesn't work. He's led around a convent repeatedly making rude noises and trying to look innocent.
 * In the remake starring Brendan Fraser, it's a pocket calculator. He has to hit "666=".
 * On Pinocchio, Jiminy Cricket tells Pinocchio (in song) to "Give A Little Whistle" whenever he needs his help ("or if your whistle's weak, yell"). Ironically, the one time Pinocchio needs his help, Jiminy isn't there.
 * The walkie talkies in Mystery Team.

Literature
"Elminster Aumar: I've learned magic enough to defeat any magelord, I believe--but I know that when any magelord gets into trouble, he'll call on another... and in a breath or two I'll have forty or more of them on my hands."
 * In The Great Hunt, The Horn of Valere calls dead heroes from antiquity to aid the blower of the Horn. "The Grave is No Bar to my Call"
 * In CS Lewis's The Lion, the Witch and the Wardrobe, Father Christmas gives Susan a magic horn that she can use to summon aid. Later on, in Prince Caspian, the horn is used to call the Pevensies to Narnia.
 * In L. Frank Baum's The Wonderful Wizard of Oz, Dorothy uses a whistle to summon the field mice.
 * In one of the Dresden Files novels, Harry earns a special favor from the Summer court of faeries which he can use to ask one boon.
 * Brave Story has Wataru rescuing a young dragon. The dragon drops a scale and tells him to find a blacksmith skilled enough to turn that scale into a flute. Then, if Wataru plays the flute, the dragon will come to his aid.
 * Taran Wanderer, the 4th book in Lloyd Alexander's Prydain Chronicles. Taran has a magic horn that, when sounded, will summon the Fair Folk to his aid, but only once.
 * Older Than Print: Huon of Bordeaux, the hero of a chanson de geste, is also called Huon of the Horn because he has a magical horn given to him by the Fairy-King, the son of Gloriantha and Julius Caesar. "if you sound it forcibly, fear not that I shall hear it, though at a hundred leagues distance, and will fly to your relief; but be careful not to sound it in that way, unless upon the most urgent occasion." The chanson is dated to the mid-1200's, but is set about 866 CE. The story itself may be much older than the chanson.
 * The Fellowship of the Rings: the Horn of Gondor. It's supposed to be very valuable and guaranteed to bring help to the one who sounds it - perhaps because it's nearly impossible not to hear. Unfortunately said help is too late for Boromir.
 * To some extent, the horn at Helm's Deep; it figuratively brings the spirit of the famously fierce warrior Helm Hammerhand to the battlefield (this heartens the defenders).
 * Magelords in The Making of a Mage were hard to kill due to being enmeshed in a web of Magically Binding Contracts allowing them to call reinforcements. Which works recursively.


 * Jiriki gives Simon a magical mirror that allows them to communicate across great distances, but warns him that although he'll try to come if he's needed, this trope doesn't apply.

Live Action Television

 * Parodied in The Mighty Boosh episode Jungle, in which Rudi gives Vince a tin whistle to play if he needs help. Vince plays the wrong tune and gets a locksmith.
 * Batman: The direct line from Commissioner Gordon to the Batcave (and the Batsignal too, obviously).
 * In The Adventures of Superman, a scientist is told to use his ability to whistle to summon Superman. However, he then has an adventure where he is in danger and so scared that his mouth is too dry to whistle no matter how hard he tries. Fortunately when all seems lost, he finds an abandoned water canteen to wet his whistle and whistles up Superman to save the day.
 * Fringe could be considered to have a variation, in the form of a bell, which was rigged by

Tabletop RPG

 * Module I12 Egg of the Phoenix. The ki-rin Da-weng allowed himself to be changed to stone so that at a future time he could be returned to normal and fight against Evil. If released, he gives the party an amulet that will allow them to summon him to aid them.
 * Dungeons & Dragons: The reversed variant of an old spell 'Succor' works this way. It enchants a statuette so that if it's broken and the password is said, the caster will be teleported to the user.

Video Games

 * Final Fantasy: In Final Fantasy X, Tidus says, "If we get separated, just [whistle] and I'll come running!" The whistle then calls him back in X-2.
 * Whilst out in the field, Captain Olimar can summon his hordes of Pikmin by giving a little whistle. He can also perform this move in Super Smash Bros. Brawl to much the same effect.
 * In the Super Smash Bros. series, Pokéballs function similarly to the trope-verbial whistle; the Pokémon will briefly fight for the character that released it from its Pokéball. Brawl introduced Assist Trophies, which are a similar item that summon non-Pokémon helpers.
 * In the Blood Omen: Legacy of Kain, After Kain failed to defeat Malek the Paladin, he seeks counsel from an oracle, who tells him Vorador is the only one who could ever defeat Malek. Kain then seeks out Vorador, who gives Kain his ring to summon him, when he is about to fight Malek again.
 * Damnd, the first boss of Final Fight, would jump to the sidelines after taking some damage and then whistle for some Mad Gear Mooks to come over and help him before resuming the fight.
 * In Red Dead Redemption, if you're outdoors and need your horse, you can press a button to make John whistle and summon the horse.
 * In The Legend of Zelda: A Link to the Past, Link acquires a whistle that summons a large bird to carry him away on the overworld. Mainly this is useful for quick transportation, but is also handy if you're swamped by soldiers or the like.
 * And in Ocarina Of Time, the third song Link learns for his Ocarina lets him talk to his friend Saria at any time, though she only gives advice and does not appear. The song he learns before that can be used to summon Epona to his position in the overworld once he frees her from Ingo's clutches as an adult.
 * And again in Oracle of Seasons, where Link can get a small flute to summon his Animal Companion. Get the idea that the Zelda series rather likes this trope?
 * In Psychonauts, Razputin can summon Agent Cruller by waving a bacon.

Web Original

 * Subverted in Order of the Stick: Celia gives Roy a medallion that will enable him to call her for help by breaking it, except that he can't break it (Celia thoughtlessly assumed that baseline humans are able to shoot lightning from their fingertips like herself), and . Oops.
 * Gunnerkrigg Court: Sir Eglamore gave Antimony a beacon (that looks like a carved stick) to break at the first sign of trouble. He promised that if she used it, he would be there to help within five seconds. (Can you say Chekhov's Gun?)

Western Animation

 * Very common on Tom and Jerry cartoons, especially in the Hanna-Barbera and Chuck Jones eras. Jerry would rescue a bulldog (sometimes Spike, sometimes not) from danger, who would then award the brave mouse a whistle, effectively becoming Jerry's personal bodyguard against Tom's scheming. Tom does eventually win in the end, though, usually due to a lucky case of third party intervention (dog catcher and a new leash law) that results in the bulldog not coming when called. The earliest short this shows up in is "The Bodyguard", Spike's second appearance. Sometimes Jerry would use a whistle to call on Muscles (Jerry's gangster cousin) instead.
 * Or a better lock on the dogcatcher's truck. In a later short it's by stricter leash laws. (Though the laws were, on that same day, turned down.)
 * Tex Avery's Bad Luck Blackie has a small white kitten summoning a large black cat in this manner. The black cat would then skip across the path of a sadistic bulldog, causing a large manner of wacky objects to fall from the sky and conk him.
 * Parodied in The Simpsons. When Bart and Lisa are enrolled in a military academy, Lisa proves herself to be such a terrible shot that the instructor awards her a special whistle, claiming he'd come to her aid if she ever needed his help in battle.
 * In Family Guy, Hugh Downs gives a magic whistle to a random bystander after he (Downs) had single-handedly defeated a serial killer (he also gives the guy John Stossel's cell number, which is apparently just as good).
 * My Little Pony has a variant: The Sea Ponies give Megan a shell that will summon their help if she throws it into the water.
 * "Never fails, you get in the bath and there's a rub at the lamp." * squeaks rubber duck*
 * For a more mundane example, the Mayor in The Powerpuff Girls has their special phone number. He rings them up any time some horrible menace is threatening the City of Townsville. Or he needs a jar of pickles opened or something.
 * There's also the Conch of Peril in SpongeBob SquarePants, that summons Mermaidman and Barnacle Boy.
 * In an early episode of Avatar: The Last Airbender Aang buys a bison whistle that Appa, his flying bison, hears and comes to.
 * Call me, beep me, if you want to reach me.
 * In the first Shrek movie, Donkey tells Dragon he'll whistle if he needs her. Shrek later calls Dragon in at a key moment by whistling, revealing that he was paying some attention to what Donkey was doing after all.
 * In Superman: The Animated Series, Jimmy Olsen had a special wristwatch that could summon Supes whenever he's in trouble.
 * It reappeared in an episode of Justice League Unlimited: Huntress got kicked out of the Justice League but she needs to ask for Superman's help. So she kidnaps Jimmy Olsen and triggers the wristwatch, knowing that this would bring Supes.
 * Somewhat lampshaded in Animaniacs: Rita busts out of the Animal Shelter in the episode When Rita Met Runt. Calling over her shoulder to Runt, she says, "If you ever need anything, just whistle." She has almost gone when Runt begins whistling "Pop Goes the Weasel." Rita quickly turns around, mumbling sourly, "Me and my overused cliches."
 * The Godzilla Power Hour: Captain Majors of the Calico has a signaling device to summon Godzilla when the crew is trouble. When that option is not available, Godzooky could howl to summon Godzilla himself.

Real Life

 * Any police or fire-fighter hotline is designed to be this.