elthe3rd
Favorite Answer
The primary point of the glowing suitcase is to give a tribute to "Kiss me Deadly" from the 1950's. In the case, they had uranium which when opened, burned up the person who opened it. I personally have never heard Quentin reveal what is in his case. If he never does, that would leave another classic element to the film. I have heard it speculated that Mr Marsellas Wallace's soul was in the case. Others have said a beautiful work of art studded with jewels.
SunyJim
It's a homage to the movie REPOMAN with Emilio Estevez.
The trunk of the car has an eerie light that melts people
Mr. Curious
Has never been officially clarified. Anyone that posts a definitive answer after this one is guessing or has fallen victim to an on-line rumor. They will NEVER give you an official site to support their theory. Most will say "his soul." But that is just one guess. Quenton T. has NEVER officially stated.
Shay Guy
It's essentially a MacGuffin (look it up on Wikipedia). There's actually a theory that it's Elvis's golden suit.
Anonymous
a yellow light shining in the actor's faces