See The Spirit. Or The Spirit.

They're from an alternate universe where Pulp Fiction swept the Oscars.

Classic theory. The briefcase contains the soul of Marsellus Wallace. The devil tore it out of the back of his head (hence the Band-Aid). Note the password on the briefcase is 6-6-6. It glows brightly and is beautiful enough to utterly disarm nearly anyone who looks into it.

• Something to point out that when Jules and Vincent kill Brett, the same color of the glow from the briefcase flashes across the screen. Soul leaving the body?
• Marsellus Wallace sold his soul for the power to run his criminal empire. But then he meets and married Mia... and the only way he can be truly fulfilled is to have his soul back, which he will pay any price to do - hiring the Wolf can't be cheap. Funny thing about souls, they are what lets people truly feel. Marsellus Wallace is a hard, ruthless man, having sold his soul, but part of the price of regaining it is to feel all the emotions that were numbed by its loss. Marsellus, the hard, ruthless criminal kingpin, must have caused immense anguish and suffering which would be reflected in his soul, if he had one. Then he regains his soul, and the suffering begins. (At the same time he's having his soul reseated, Mia Wallace overdoses on heroin and dies - whoever Marsellus sold his soul to wants it back, and takes Mia's soul in exchange.) A soul sold to the devil is cursed by God, and brings ill fortune to whoever possesses it. Only Jules Winnfield walks away whole, a man freshly set on a path of righteousness - judged, and declared worthy of redemption.

He survives the shootout at the end and has apparently escaped custody and is, now incognito, trying to get the jewels back.

• Also, Pink's real name is Carl Showalter.
• If the jewels are in there, why does it glow?
• Special light for a special case. It could have been lined with gold foil and a light bulb that turns on when opened along with the diamonds.

Mr. Orange survived being shot. After all he survived that long already and we never see where he's been shot. Plus people have survived shots like that. Mr. Pink co-operates with the police, tells the location of the diamonds and gets parole. After all we never see him kill anyone and he's the only one without a back-story. For all we know he could be scot free other than the robbery. So then Mr. Orange gets a new identity, that of a small time crook to retrieve the diamonds and hooks up with Amanda Plummer. He gives back the case at the end because he knows Jules and Vincent both work for Marsellus.

• You think Orange survived being shot in the head?
• Mr Pink killed a few policemen at the start of the film, so I doubt he would be let out so easily.
• Some theories, due to ambiguity since the last bits of Reservoir Dogs only show Mr. White thinking about shooting Orange, say that White was killed before he could plug Orange. Therefore, it could be plausible that Orange survived. Not to mention The Bride survived a freaking gunshot wound to the head.

Both give off a golden glow, etc.

• Impossible. The glowing thing in the Trunk in Repo Man kills who ever looks at it.
  • The people who do look inside it all die. If I'm not incorrect that is.
    • You are incorrect. The guy in the diner looks into it and survives.
    • For now.

The Ark makes any army marching with it invulnerable, which explains why Jules and Vince are able to have weapons fire at them at point blank range with no injury (while holding the briefcase). Also, the briefcase shines with an interior light, like a weaker/smaller/more aged version of the opened Ark in "Raiders."

• Vince survived looking into the briefcase. This might mean the briefcase is the Ark from the Xenaverse. While the Indiana Jones Ark kills whoever looks at it, the Xena Ark kills whoever looks away from it.
  • But Vince did die by the end of the movie. The Ark may have "cursed" him to be shot by Butch rather than melting his face off.

Oh come on! Can we please keep it somewhat plausible??

• Seconded! The glow might be just a light built into the suitcase, like the ones that you see in glove compartments sometimes. When you accept this theory, the possibilities of what people are really reacting to in the case open up quite a bit.
• Maybe it's the Most Valuable Lightbulb EVER MADE?
  • Self illuminating light bulb, therefore it would be a self-powered one which would be a stone's throw away from perpetual energy/free eternal lasting energy. Which leads me to believe Marcellus Wallace and his gang work for Greenpeace.
• Word Of God: It's a lightbulb. A supernatural one. At least, it is if you accept that Watson's first and middle names were Arthur Conan.
  • No, Word Of God said that in real life they used a yellow-orange light bulb as the prop. However, there has never been any Word Of God explanation for what is in there in-universe and presumably there never will be. See the entry on The Walrus Was Paul.

It gives off a golden glow, brings tears to some characters' eyes...

What else would mean something to a mobster, would be carried in a discreet briefcase, and glows golden when the briefcase is opened? Characters getting emotional about its content is simply their greed overcoming them.

• Gold Bars are heavy; it's difficult for even one to be carried, let alone a couple in a suitcase. The object(s) in the suitcase must be lighter than Gold Bars, yet similarly or even more valuable.
  • Or, they could be gold leaves.

Glowing Batman, who is about to give them all the beating of their lives; seeing him in there just fills everyone with awe. But he's only two inches tall, and it's the middle of the day so he's not so scary, and so they can just close it up again. Tiny little glowing awe-inspiring Batman!

• Tiny little glowing awe-inspiring Batman? You, sir, win.

Yes, it will kill those who look upon it - but it'll take a while...

• Already been done.
• But of course. Where do you think Quentin got the idea in the first place?

That '70s Show tells us that a film canister full of marijuana glows bright green. A suitcase full probably fills the mana gauge completely and starts glowing gold.

• Alternatively, it is a Gold Herb from the Resident Evil series and the marijuana in That '70s Show was just a lesser Green Herb. Although, that suggests the herbs in Resident Evil are marijuana, which would explain a lot...

This might seem a little odd, but the briefcase contains something rather mundane that belongs to Marsellus - perhaps some cheap jewellery, or some kind of souvenir. Vincent and Jules become transfixed upon looking at it, not because it's something particularly special in itself, but because they're trying to work out why Marsellus finds it important: they reason that Marsellus is an important and dangerous man, who must therefore want this object only if it is important or dangerous. Similarly, "Pumpkin" observing "It's beautiful" might simply be trying not to offend the guy pointing a gun at him.

• The Gold Watch sequence gives credence to this idea.
• But Pumpkin calls it beautiful before he knows Jules has a gun on him.

Marsellus became aware of Butch's attachment to his father's watch, and so he hired someone to steal it. The guys whom Jules and Vincent were hired to kill tried to pull a fast one on Marsellus and grabbed as much stuff of his as they could find - including the case, which Jules and Vincent later returned. Marsellus expected that Butch would eventually mention to him that the watch was missing; he would then promise to find it and shortly thereafter produce the watch. Marsellus presumed that Butch would feel indebted to him and less likely to screw him over. Apparently, his plan failed.

• If Butch's gold watch was stolen, then why was it right where he left it in the apartment?

Impossible. In the music video for "Oops, I Did It Again", Britney Spears as the queen of Mars clearly collected the necklace so she could give it to her astronaut boyfriend.

• To be fair, the movie is set in the mid-eighties to early nineties, before Britney Spears was more than just a wee Mousekateer and before Mars landers were pretty common. It's possible that the necklace eventually made it's way to Spears by this time, after getting tossed around in a massive mafia war that killed or incapacitated Marsellus and got into the hands of a music exec who wanted to reward the new pretty to the first pop mogul to set up a fanbase in space: an alternate universe Britney Spears, who instead of going mad and having a massive meltdown in 2007, decided to go into astronaut training.

The one that says Bad Motherfucker.

It's just briefcases all the way down.

• "What's in the smallest breifcase?" "Porn."
  • Is one of them a Clash of the Titans lunchbox?

Everybody wants it, and it transfixes those of weaker wills. Some people are willing to kill to have it. Jules is made of stronger Motherfuckin' stuff, and so has no desire for it and will give it to his boss willingly. Oh, and the Ring isn't likely to let its new bearers be killed by something so mundane as a fellow with a BFG.

• This, of course, means Jules is really Tom Bombadil.
  • Ah, that would explain a lot. Oh, no, wait, that just raises further questions.
  • Okay, Tom Bombadil being played by Samuel L. Jackson is now officially the most awesome thing ever.

Its only value is that it glows and looks hypnotically beautiful to anyone who sees it. The briefcase reduces the effect it has on the holder, so that it can be aimed and used by a non-spellcaster, or simply looked at and enjoyed without becoming unable to ever close the suitcase.

Tangled up Christmas lights, and wide-mouth booze.

The film takes place in the Fallout universe - or maybe Fallout takes place in Pulp Fiction universe, especially since both pay homages to popculture. That's why you don't see computers (because they would be too huge and limited to bases and factories) and everything has that old-style feeling. It takes place shortly before 2077. Butch ran away from Marsellus to find a suitable vault. The game also provides a Shout Out to it by having a boxing ring in the second game. Marsellus needed the G.E.C.K to create New Reno when he left the vault. And the motive for Bishop's revenge on Vault City was because Lynette stole Marsellus' G.E.C.K to create the city and left him with only fundaments. Also, look at Angela Bishop's sprite - black hair, addiction to Jet, is related to a mob boss... she's an Expy of Mia Wallace! Jules after the incident with the "miracle" realized that he isn't doing a plain ol' job. He now knows that what he protects is for ensuring a better future.

• Lynette is younger than Vault City. Of course, it might be an inherited feud, with the Bishops keeping a grudge against Vault City and its leadership.

That golden glow looks suspiciously similar to the one witnessed by Rose Tyler in "The Parting of the Ways". Just saying...

Everybody who looks into it is transfixed, but has a different reaction. Vincent looks confused and almost scared because it shows how he dies. Honeybunny and Pumpkin see that they give up their lives of crime and live peacefully thanks to Jules, hence "It's beautiful." Jules never actually sees what's inside, so he's able to become a free man with no knowledge of his future.

Which is why it's so highly vauled in the criminal community.

And Jules and Vince are Templar agents attempting to get the Briefcase from Marsellus to deliver to Abstergo Industries.

• And after repenting, Jules joins the Assassins. Thus, we have Assassin Samuel L. Jackson.

Really now, we're talking about a crime lord and his hitmen, some punks with the guts to steal from a crime lord with hitmen, and some small-time muggers. A suitcase full enough with drugs is definitely enough to hold any of their attentions.

Jules wasn't lying!

• Specifically, that shiny, really high-quality commissioned over-the-shoulder thing he was going to wear at the end of the week while out with Mia Wallace. Jules wasn't being facetious, he was asking if Wallace was in drag when the guy saw him or not (apparently not, from the confusion).

It's incriminating evidence that needs to be taken to an associate without falling into the wrong hands, but is useless to anyone who isn't the cops (since they'd be killed if they tried to tell the police, and would probably not be believed anyway). The people who understand it are amazed at the information, the people who don't are puzzled, and Pumpkin thought that the embossed gold-leaf seal was beautiful. The glow is the lightbulb in the case reflecting off of the contents, including the aforementioned golden seal.

Warning: Direct exposure to the Source may result in unwanted regeneration immediately following such injuries as gunshots. If you are exposed to the Source, please contact your local terraformist medic for immediate treatment. The Source is not to be handled by fish-men, gangsters, or sad onions under the age of three.

I can't take credit for this one: an old cyber pal of mine on a now long since defunct Tarantino forum came up with it. But I always liked the notion. Don't know how much a Golden Ticket would glow but I'm sure there are ways to Hand Wave your way out of that (I wouldn't care to try) and can't you just see Quentin Just-Call-Me-Mr.-Humorous-Homage doing it?

Look, this is Tarantino we're talking about.

Since the working title for pulp fiction was black mask.

This explains the golden glow when it's opened, as well as the "miracles" bestowed upon those who carry it. People shed tears of joy upon looking at its contents: an unlimited amount of root beer cans, the drink of the gods.

Doc Brown told the Libyans to steal the plutonium and drop it off at a safe house. The plan was once the authorities stopped looking for it, he'd pick it up to make a nuke. Then, he paid Marcellus to send his men to the apartment and make it look like the mob stole the briefcase full of plutonium so they wouldn't come after him for not building a nuke. Somehow, they figured out he paid Marcellus and as a last ditch effort, offered them a nuke shell full of pinball parts to buy more time for building the Delorean.

It shines brightly. It's described as beautiful. It's very lightweight (look at little effort Vincent uses turning it over when he puts it on the counter in preppy kids' apartment). Obviously the preppy kids are Lost Boys who owe alot of money to Marcellus, but they don't have the money so they catch Tink, tie her up and put her in the briefcase, then they kick back, eat some Big Kahuna burgers and wait for the pick-up. KNOCK KNOCK.

The light is Elpis, the hope that remained in the box after all the world's evils escaped.

The theft was very high-profile: "Is that what I think it is?"

It's not what Ringo/Pumpkin thinks it is- Either a forgery of the actual briefcase, or not the briefcase from {=D Mf M=}. Whichever it is, he's a Know-Nothing Know-It-All.

Pumpkin thinks it's a birth certificate. Honey Bunny just thinks it's some sort of shiny, awesome certificate of coolness because of the gold edging/frame that was added after-the-fact.

And we finally see it in the Stinger of Thor.

• It all makes sense now. Jules quits a life of crime and takes off with the Cosmic Cube and retires as a piano player, only to be shot during the wedding massacre... right in the eye, in fact. He then joins the US government, using the Cosmic Cube as leverage to become the leader of SHIELD.