It's a powerful magical artifact, unique high-tech gadget or just an extremely valuable prize. As long as the hero can hold on to it, they will be victorious in the end... which is of course why they are constantly dropping it or having it stolen from them. If the item is the source of their power, this will serve to create a frequent Drama-Preserving Handicap by forcing them to solve a problem by themselves that would have been trivially easy if the absence of the item hadn't caused them to be Brought Down to Normal. Either way, both tense scenes and longer plot arcs can be created by the hero desperately trying to get the item back.
Sometimes this is justified with the item being an Empathic Weapon or Artifact of Doom that has a will of its own and either doesn't want to stay with the protagonist or takes a perverse delight in "testing" them by withdrawing its help and seeing how they get by without it. Other times, though, it's just another example of protagonists having the worst possible luck as long as that makes things more exciting.
Another possible variation of the trope is the magical artifact of Game Breaking power that the protagonists need to locate for a single, critical use. Having employed it to resolve their current troubles, they will promptly lose it, which is explained by the item being too magical and mysterious to stay in any one person's hands for too long.
Contrast the Loyal Phlebotinum, which won't abandon you and will actively try to get back to you even if you should lose it anyway, and Clingy MacGuffin, which you can't get rid of no matter how much you might want to. Note that in some cases, whether a MacGuffin is Slippery or Clingy/Loyal depends on your perspective. A talisman that is trying to return to its true owner will be Clingy in regards to that owner, but Slippery to anyone else who tries to hold on to it.
If this trope is sped up to the point where no one can hold on to the object for more than a few seconds, you will end up with a MacGuffin Melee.
Examples of this trope include:
Anime & Manga
- Dragon Ball: The eponymous wish-granting objects scatter across the world after being used (and are completely inactive for up to a year). However, the heroes eventually become so strong that gathering them becomes an unnoteworthy task done off-screen.
- Demon Slayer: Kimetsu no Yaiba: The "Blue Spider Lily" is a mythical variant of the Spider Lily flower, and the key ingredient to a medicine that would cure the series' Big Bad of his weakness to the sun. However, it's very hard to find, and ultimately Muzan choses an alternative method.
- One Piece: The Five Elders outright state that the World Government has been trying to find and capture Luffy's fruit for over eight hundred years, only for it to constantly slip their grasp. As Zoan fruits have wills of their own, they speculate that the fruit was deliberately avoiding them while looking for a host that'd "agree" with its particular values of joy and freedom.
- Cheshire (Miraculous Ladybug): The Black Cat Miraculous, which keeps slipping from one set of evil hands to another, until it ends up in Marinette's hands and she becomes its first good user.
- Children's Party at the Palace: The Queen's handbag was caught in multiple hands ever since Her Majesty forgot to take it with her, first being stolen by Burglar Bill, then confiscated by Mr. Plod, and finally given to Tracy Beaker so that she can return it to the Queen.
- The Lord of the Rings: The One Ring wants to return to its true master Sauron, and will subtly influence events to make that happen. In the backstory, it abandoned first Isildur and then Gollum at a critical time. In the film of The Fellowship of the Ring it somehow slips away from Frodo in the avalanche on Caradhras. This is physically impossible because the Ring was not in his pocket, but carried on a chain around his neck, and the chain is intact when Boromir picks up the Ring — but the Ring, being magic, does it anyway. It calls to the Nazgûl every time one is near, and during The Two Towers, it also manipulates Frodo into offering it to a Nazgûl during the siege of Osgiliath. It is only thanks to Sam's interference that Sauron doesn't get the Ring back.
- Secret Agent (1936): When Brodie/"Ashenden" and the General find a contact dead, they find in his hand a button, evidently torn off in the struggle. When they go to a casino to meet Elsa, the button is accidentally dropped onto a gambling table. Since it looks the same as his own chips, an experienced mountaineer assumes it is his and takes it. Ultimately downplayed in that once they recover the button it disappears from relevance in the plot.
- Book of Swords: Coinspinner will grant you good luck for as long as you can hold onto it, but if you take your eyes off it for even a moment, it can vanish and reappear anywhere in the world.
- Conan the Barbarian: Robert Jordan's novel Conan the Magnificent plays with this trope. The villain's (literal and figurative) Dragon can only be slain by a certain magical sword, which can only be granted to a worthy wielder, and only once in a lifetime. If the true wielder loses the sword, it will eventually find its way back to the sacred grove where it is normally kept, and only then can it be granted to a new wielder. Conan is not the chosen wielder, and so from the moment he picks up the sword he's doomed to lose it - but since by the time he gets his hands on it, he's standing right in front of the dragon, he doesn't actually need to hold on to it for more than the few seconds it takes him to slay the beast.
- Cytonic (the third book in Brandon Sanderson's Skyward series): Spensa's reality icon turns into one of these when she buries it and comes back to find it missing. It's apparently a common occurrence in the Nowhere. This is because they are actually taynix using their cytonic abilities to disguise themselves and hyperjump. Spensa's is actually Doomslug, who was rather miffed that Spensa buried her in the dirt.
- The First Law: The short story Tough Times All Over follows a mysterious package as it switches hands repeatedly over the course of a night, time and again getting stolen or passed along like a hot potato, and ultimately ending up in the hands of the same courier who lost it in the first scene.
- Tolkien's Legendarium: The One Ring is a Slippery MacGuffin to the heroes because it's a Clingy MacGuffin to its evil creator Sauron, and will subtly influence events to bring it back to its master (as characters mention, "it wants to be found" which is why burying it or casting it into the sea won't work).
- In the backstory, it abandoned Isildur at a critical time.
- In The Hobbit it slips away from Gollum, hoping to be picked up by a goblin, but instead is found by Bilbo Baggins.
- It tries to do the same to Bilbo at least once during his adventures, when it slips off his finger and allows the goblins guarding the back-door to see him. Fortunately for him, it slips off while his hand is in his pocket.
- During the years between The Hobbit and The Lord of the Rings, Bilbo noticed that it would sometimes slip off a finger that it had been tight on.
- During The Lord of the Rings, it calls to the Nazgûl every time one comes near, tries to get several of Frodo's companions to take it from him, and finally succeeds with Gollum.
- A Lost Letter: The love letter starts by being lost by Zoe in a moment of carelessness, found by the Drunken Citizen, stolen from him by Caţavencu, then lost again, then found anew by the Drunken Citizen, who returns it to Zoe.
- Tennis Shoes Adventure Series: The Sword of Contrarium, or Silver Sword, always seems to be getting dropped or stolen or falling in just the right way. Leaving it in a hotel room for an hour almost gets it stolen, which leads to Jim and co. carrying it on their person at all times.
- The Shannara Chronicles: Wil Ohmsford can't seem to keep hold of the Elfstones for more than five minutes in a row. You'd think he'd at least tie that pouch to his wrist or something.
- Supernatural: The episode "Bad Day at Black Rock" features a magical rabbit's foot that grants incredible luck as long as you have it, but which also curses you with equally bad luck if you lose it. Naturally, part of the enchantment is that you'll always lose it before long.
- Witchblade: The eponymous artifact is said to be prone to abandoning its wielder in her time of need, something Sara gets to experience a few times over the course of the series. Flashbacks show that previous wielder Joan of Arc died crying out to it, demanding to know why it had betrayed her.
- A non-supernatural example would be Old Face Andre's ring in The Wire. First taken as a payment by Marlo, robbed from Marlo by Omar, taken from Omar by Officer Walker, and then taken from Officer Walker by Michael.
- Demon: The Fallen: The City of Angels supplement mentions a magical sextant created by the demon Gripontel. It can lead its bearer to any destination, but will often mysteriously disappear after doing so.
- Dungeons & Dragons 4th Edition: Unlike in other editions, magical artifacts are always intelligent and will always eventually disappear forever from their bearers. Depending on the artifact's disposition and relationship with its bearer, this could mean anything from a fond But Now I Must Go scene to vanishing right when the bearer needs it most.
- Villainous (Ravensburger):
- Dr. Facilier's Blood Magic Talisman is integral to his objective, or at least controlling it is. The problem is that whenever a weak Hero comes into his realm they steal it, requiring that hero be vanquished in order to reclaim it.
- Syndrome's Remote is required for Syndrome to defeat the Omnidroid V.10 for his win condition, but if any of the Heroes (except Jack Jack) are played, they immediately grab it, preventing Syndrome from using it. Fortunately, the V.10 will act as a powerful ally when this happens, as it wants the remote as well.
- BIONICLE: The Mask of Life, which could never stay in any one being's hands for long, until Matoro finally acquired it for good in BIONICLE Legends.
- Chuchel: The only thing you want is that one cherry. Good luck keeping it more than a few seconds.
- The source of the conflict in Disney Mirrorverse is the Fractured Mirror, which summons crystalline extradimensional entities known as the Fractured. The villains who possess it use it for various schemes, but after it drains power from so many Stellar Crystals, it vanishes and finds a new villain to wield its power. Maleficent started with it before the story began, but it goes over to the likes of Jafar, Oogie Boogie, and Hades before long, ensuring the conflict continues.
- The Elder Scrolls: The Daedric artifacts fit. They are extremely powerful and legendary magical items (often weapons) that are granted to mortals by their associated Daedric Prince, typically by performing a service for the Prince in question. Given that most of the artifacts make recurring appearances throughout the series, it is explained in-universe that these artifacts have a will of their own and never stay with a particular wielder for long. In a few cases, to acquire the item, the Daedric Prince has you relieve it from its previous master (usually lethally).
- League of Legends: The shards from Riven's blade help her remember her past, but keep disappearing after she gets them. Subverted when it turns out she doesn't care for others' obsession with her past defining her, and has been burying them so she won't remember.
- Marvel Ultimate Alliance 3: The Black Order: The Infinity Stones end up switching hands multiple times throughout the game. For instance, the Power Stone ends up being in the hands of the Hellfire Club, the X-Men, the Sentinels, Magneto, and Cull Obsidian over the course of the game's story.
- Nethack: The amulet of Yendor. The entire game is about finding it (and offering it to your god). But one of the bosses will do its hardest to reappear and take it from you. Oh, and beware shoddy plastic knockoffs. It would be ever so embarrassing to offer one of those instead.
- The Sonic the Hedgehog series has the Chaos Emeralds in most instances; given their power, it is unlikely the heroes or villains start with the entire set ready to go. The one time Sonic did, however, Eggman planned around it, and they get shot into space along with the hedgehog.
- Darths & Droids: Referencing the One Ring that "wants to be found", there is the Lost Orb of Phanastacoria which "wants to be lost". It's only a matter of time before it becomes the Lost Orb of Phanastacoria again.
- Shady Oaks SMP: Kindness the sword has changed hands twice in the first couple of days of the server's existence.
- The Karate Kid: The miniature shrine with magic powers, once it's stolen from its resting place on Okinawa. Good luck on anyone — heroes included — holding onto it for long, as it keeps escaping from Daniel's grasp by random chance. With the regularity this happens, you almost wonder if the shrine itself has a part in it.