The Pulp Fiction briefcase is, in some ways, similar to the black monolith in the 1968 Stanley Kubrick film, 2001: A Space Odyssey. First, the two objects are similar in physical appearance: Both are flat, black, and rectangular-shaped. Also, both objects are portrayed in their respective movies as being mysterious - there's a certain amount of mystery surrounding the origin of the monolith in A Space Odyssey, and the Pulp Fiction briefcase is mysterious in that its contents have been considered by many people to be uncertain.
Above left: The Space Odyssey monolith is the rectangular black object jutting upward from the rocks, in this shot from the 'Dawn of Man' segment of Kubrick's movie. Above right: The first time we see the briefcase in Pulp Fiction, it is shown being handled by Vincent Vega in Brett's apartment.
Another correspondence between the briefcase and the monolith is that the first killings in Pulp Fiction occur very soon after the briefcase makes its first appearance , near the movie's beginning in Brett's apartment. Similarly, the first killing in 2001 takes place not long after the monolith makes its first appearance (in the above-mentioned 'Dawn of Man' segment).
Shortly after we see Vincent handling the briefcase in Brett's apartment, one of Brett's cohorts is shot and killed by Jules (above left), and not long after this, Brett himself is killed (above right).
Above left: Man's early ancestors, the members of a tribe of 'ape-men', begin to investigate the black monolith in A Space Odyssey. Above right: Not too long after this encounter with the monolith, a member of the tribe that encountered it kills a member of a competing tribe, by striking him with a hand-held bone.
The overall point here is that the Pulp Fiction briefcase is a representation of the Space Odyssey monolith.
