Pulp Fiction: what was really in the briefcase?

What the hell's in the case? That's just one of the questions that's been hotly debated on the net (along with others, like, does a foot massage mean shit?) since Quentin Tarantino's Pulp Fiction hit screens 20 years ago, and became one of the most iconic films of the 90s. The follow-up to his indie debut hit, Reservoir Dogs, it brought that movie's raw violence and pop-culture banter to a whole new level, with a complex and exuberant weave of mobsters and two-bit crims created in comic, bloody homage to hardboiled crime novels and the movies he'd grown up on. It starts and ends with a chaotic diner hold-up in which the possessions demanded from patrons by small-crime messes Pumpkin and Honeybunny include a briefcase carried by off-duty henchmen Jules and Vincent. Ordered to be collected by kingpin Marsellus Wallace, the mysterious case drives the action throughout the movie – though we never see what's inside. As Pulp Fiction's 20th anniversary nears, we look at the top theories of what it might be.

DIAMONDS

Co-writer Roger Avary has said diamonds were mooted when they were penning the script, but that was rejected as too predictable (Tarantino had just used that idea in Reservoir Dogs, after all). Besides, in a gangster world in which a case of diamonds is ho-hum or at least par for the course, seasoned hitman Vincent seems mighty awed at the sight of the spoils. Plus, the case emits a golden glow. Gold bars? Too heavy for this easily toted prize.

ELVIS'S GOLD SUIT

Okay, now that would drop jaws. Tarantino's reign as the king of pop-culture pastiche with a penchant for referencing other films and in-jokes for cineastes has led some to bet that inside must be the gold lamé Elvis suit from True Romance. Why would it be coveted by Marsellus Wallace? It would certainly impress his wife Mia, regular at 50s-themed diner Jack Rabbit Slim's. At least, more than an accidental massive line of heroin.

A SMALL NUKE

It could also be nuclear, in homage to Robert Aldrich's classic 50s noir Kiss Me Deadly, in which a Los Angeles private eye searches for a glowing case filled with radioactive material.

THE SOUL OF MARSELLUS WALLACE

The most persistent and ingenious theory is that what is inside the case is nothing short of the soul of gang kingpin Marsellus Wallace, who sold it to Satan and is trying to get it back. The imposing mob boss wears a Band-Aid on the back of his neck, reportedly because actor Ving Rhames has a scar there he wanted to hide for the iconic over-the-shoulder shot, but it's also been argued that when the devil takes your soul he takes it from the back of your neck. This neat esoteric factoid doesn't seem to be in the Bible, as messageboard amateur sleuths claim, or in some vague version of "Chinese mythology" (correct us if Google has served us poorly), but we like this theory's style. It would also explain why bullets miraculously miss Vincent and Jules in an apartment shooting – divine intervention is surely more likely to help your ass when you're on soul-saving business. And the briefcase combination? What else but 666.

THE HOLY GRAIL

At any rate, the orange light bulb shoved in the case on-set last-minute creates a luminous glow that seems supernatural – and if it's been taken back out of storage from the Indiana Jones franchise, it could even be the Holy Grail inside. It's a symbol of divine grace – so Jules and Vincent's lucky escape also fits with this theory. Anyone who casts eyes on the Grail is said to become, like Pumpkin, dumbstruck (though, granted, that mess of a hold-up artist seems mentally unequipped to be blasé in even the most banal of situations).

A MACGUFFIN

Hitchcock loved to use MacGuffins (say what?) in his films, and popularised the term in the 1930s. It comes from the story of two men on a train in the Scottish Highlands. There's a package on the baggage rack. One man asks what's in it, and the other tells him it's a MacGuffin – a contraption for trapping lions. When told there are no lions in those parts, he replies: "Oh, then that's no MacGuffin." In other words, a MacGuffin is nothing in and of itself – it's just a device for moving a story along. So, it doesn't matter what's in the case – just that the characters are after it. Tarantino himself says there's no one explanation. But should we really trust that spoilsport?

THE STUFF THAT DREAMS ARE MADE OF

Keeping it hedged within "whatever you want it to be" territory, it's also been suggested the case is a magic mirror of sorts that shows us our ultimate desires. There are loads of cinematic precedents for this. A room in a forbidden Zone in 70s Russian SF flick Stalker is said to offer adventurers a glimpse of their innermost yearnings, and in noir The Maltese Falcon a private eye refers to the titular bird statuette – which to today's untrained eye might as well be thrift-store tat – as "the stuff that dreams are made of".

AN OSCAR

Is it an Oscar statuette Marsellus has procured for his wannabe actress wife? Some message-boarders have joked that it is – or that it represents the Academy hopes of Tarantino himself. He bagged one for Best Screenplay for his efforts here, so if so, the suitcase delivered.

Pulp Fiction is running exclusively at Cineworld cinemas from today