Holy Ghost
Holy Ghost
[The Pope stands behind a table.] Pope: This is a disaster. Ghostbuster (off-screen): Is it really that bad? [The Pope seen from the side in white on a black background. The text is in white:] Pope: Do you know how much scripture we'll have to revise? Ghostbuster (off-screen): Look, we've apologized – [Zoom out from the bishop] Pope: I mean, we can't have a trinity with just a Father and a Son! Ghostbuster (off-screen): Again we're sorry. [The four Cueball-like Ghostbusters with their proton packs.] Pope (off-screen): Sorry's not enough. Guards, take their proton packs. Ghostbuster: Hey, we were just doing our jobs!

The majority of Christian sects (including Roman Catholicism ) profess belief in the conception of a singular God wherein there is a mysterious unity of three distinct 'persons' who share in one another's divinity, in a concept called the Trinity . The three persons are conventionally called the Father , the Son , and the Holy Spirit — but in more archaic English usage, the third person was referred to as the Holy Ghost .
The 1984 movie Ghostbusters was based on the premise that ghosts exist and that four unemployed men had access to technology that could trap such ghosts. These men formed a business as Ghostbusters, and an important tool in their arsenal was a so-called "proton stream" powered by a wearable backpack. These streams would prod or stun ghosts, allowing them to be maneuvered into traps. Throughout the movie, the Ghostbusters reminded each other 'not to cross the streams', as this was supposed to cause a disastrous reaction, until the climax of the movie where crossing the streams was required to banish the main antagonist.
Here we see that the Ghostbusters have apparently just encountered and eliminated the Holy Ghost, and are being taken to task by the Pope , the leader of the Roman Catholic Church. He points out that much of Christian theology is grounded in the doctrine of the Trinity and is unwilling to accept the Ghostbusters' apology.
The title text is a play on a short Catholic prayer called the Sign of the Cross (the physical motions of which involve touching the forehead, chest, and shoulders), the practice of which is colloquially called 'crossing oneself', and on the danger of the Ghostbusters' 'crossing the streams' and touching two proton streams together, which in Ghostbusters canon causes an explosive chain reaction in all nearby atoms.
[The Pope stands behind a table.] Pope: This is a disaster. Ghostbuster (off-screen): Is it really that bad? [The Pope seen from the side in white on a black background. The text is in white:] Pope: Do you know how much scripture we'll have to revise? Ghostbuster (off-screen): Look, we've apologized – [Zoom out from the bishop] Pope: I mean, we can't have a trinity with just a Father and a Son! Ghostbuster (off-screen): Again we're sorry. [The four Cueball-like Ghostbusters with their proton packs.] Pope (off-screen): Sorry's not enough. Guards, take their proton packs. Ghostbuster: Hey, we were just doing our jobs!
