So “Grand Theft Auto V” comes in the mail and I know the time has come to dump my girlfriend, only I don’t have a girlfriend because I’ve been saving my freedom for “GTA V.” I whistle the “Andy Griffith” theme as I skip out of the mailroom.

I cross the campus. The sun’s shining, so I flip it the bird. F—-r’s just gonna explode and destroy everything in about 8,000 years anyway. And that’s fine. C’est la vie. Why do I need to climb a mountain or master the made-up application of numbers? Where the heck’s the achievement in the ability to bounce a ball? And f—k dancing. I’d rather sit down.

I put the sacred package between my legs and try to ensnare my keycard, which has sunk into the Mariana Trench GAP hath sewn for my hips.

I realize: “There’s a whole world between my legs.”

As I climb the steps, panting, I wonder, “What do we know about ‘GTA V’?”

Well, it’s been in development for five years; “GTA IV” came out in 2008. We know that it follows in the series’ tradition of telling crime stories, basically low-grade pulp: they make De Palma’s “Scarface” look like “Citizen Kane.” They are funny: the writers haven’t taken themselves too seriously, have a good, juvenile sense of humor, and litter the games with crude social satire.

But whereas past “Grand Theft Auto”’s have followed a single storyline, in “GTA V” one can play through three interwoven storylines, meaning one can alternate between playing as three different characters. In an extraordinary development that would shake the universe were it under our control, players can switch between these three different characters at any point in a single scene: you might be hanging from a window “Matrix”-style and decide to switch to the second character, on a rooftop, sniping, or to the third, waiting in the getaway car.

As I dwell on this, still climbing the stairs, I lean over to compensate for the similarly extraordinary development in my jeans.

We know that the size of the game’s map, which is to say the size of the world in which the game takes place, is the size of the map from “GTA V” developer Rockstar Games’ “Red Dead Redemption,” which, if one spent an hour a day playing, one wouldn’t have explored for at least a month, combined with the map from “GTA IV,” which would take roughly three weeks to explore, and then some.

I wonder, as I reach the top of the stairs, feeling as though I’ve just completed a marathon (of “Lord of the Rings,” that is), if it is possible to go around the “GTA V” world in 80 days.

I knock over four people on the way to my room. One of them yowls for help, but no one comes. I ignore my roommate. When he keeps talking, I turn and roar at him like one of the crazed bikers in “Mad Max 2.”

I don’t know if he leaves, because the “GTA V” installation screen has come up on my TV. Were this “Videodrome,” I’d touch the hell out of that monitor.

This is a rebirth—like waking up in those birthing sacs from “The Matrix,” unhooking yourself, bursting out, only that world was apocalyptic and dystopic and sad and really messy, and the sun never shone, and although I could’ve just described my room, right now it’s filled with light, and truth, and gunshots, because “GTA V” has begun.

It’s a hostage situation. I gotta shepherd a few scared hostages into a room where we can lock ‘em up, then escape from the cops. Things go wrong.

It’s like the series is spoofing itself… yes… I’ve picked up on this… I’m already getting cleverer…

I get to f—k with the legendary “GTA” radio stations. There are 17 in “GTA V,” a vast compendium of music spanning every possible genre, except classical music, because the people behind the “Grand Theft Auto” games aren’t sadists.

There’s even talk radio. I overhear one caller say, “My wife can’t pregnant no more. Her uterus is ravaged like the projects!”

A self-possessed woman talks with an interviewer about an absence of real movies. She says, “And that’s why we’ve seen this sudden spike in gang-affiliated crimes—there are no movies to warn us not to do bad things anymore!”

When I run, it looks real. The passage of time seems real, but sped-up. Wasted time has been eradicated. I can explore areas that look like rural New Mexico, like something out of “Paris, Texas.” I can climb a mountain that makes Vermont’s titular hills seem like dirt mounds. Word has it there’s a ghost up top, and Bigfoot might be around. When my character is drunk it seems real. That prostitute looks real—va-va-voom!

Cue “Law and Order” music.

Thomas Benton was found dead in his room on Sept. 17. The coroner ruled the cause of death: “Grand Theft Auto V.”

“Grand Theft Auto V” sold 800,000,000 copies on its first day. It’s the fastest-selling entertainment product in history.