The following script is from "Hoop Dreams" which aired on April 19, 2015. Lesley Stahl is the correspondent. Shari Finkelstein and Jennie Held, producers.

Every once in a while, we come across someone with an amazing ability. A power so unusual, so unexpected, and so fascinating, it becomes a story. That's why we're telling you tonight about a man named Bob Petrella, and a college basketball team that gives a whole new meaning to the phrase "hoop dreams."

Bob Petrella CBS News

Bob Petrella is one of the only people in the world who possess the extraordinary ability to remember virtually every day of his life. But it turns out there's something else in Bob's memory too: a basketball team whose history he has charted for more than 50 years called the Holland College Golden Knights. Holland has played in 10 NCAA championships -- and won five. Never heard of them? Well, there's a reason why you haven't.

Lesley Stahl: How old were you when you first created the basketball team?

Bob Petrella: I was 13. January 3rd, 1964, it was a Friday.

[Bob Petrella: Holland coming down, up by only two.]

You haven't heard of Holland College because it doesn't actually exist. They're an imaginary team that Bob Petrella made up. This is our simulation of one of Holland College's games, with Bob doing the play by play. He's been imagining these games for 50 seasons, and he remembers every one of them...

Lesley Stahl: Who were the starting forwards in 1983?

Bob Petrella: The starting forwards in '83 were Otis Pooky and Brad Jasmine.

He can describe them.

Lesley Stahl: How tall were they?

Bob Petrella: Otis Pooky was 6'6 and Brad Jasmine was undersize at 6'5 but real bulky.

You can almost forget...

Lesley Stahl: Tell us about the years they made it to the NCAA finals.

Bob Petrella: They went to the final between '73 and '75. They won in '74. They went in '77, '78. '80, they lost.

That none of this is real.

Dr. James McGaugh: I mean, this is really unusual. I have never heard of anything like this before. Never.

[Dr. James McGaugh: You made that up though?

Bob Petrella: Of course. Yeah.]

Dr. James McGaugh is a leading expert on memory and cognition at the University of California, Irvine.

Dr. James McGaugh: It's not just a series of facts that he recalls, like the memory of the names of the presidents or the alphabet. It's a whole story that he has. And the story is rich in detail because you can ask him more and more questions about each of the players.

Lesley Stahl: And it's five people every year for 50 years?

Dr. James McGaugh: That's right.

Lesley Stahl: Plus the coach and the college president--

Dr. James McGaugh: One could not do this without the kind of memory that Bob has.

The kind of memory he has is called HSAM - highly superior autobiographical memory - and Bob, along with actress Marilu Henner, was one of the first people ever discovered to have it. We featured them in a story a few years back.

[Dr. James McGaugh: A 7.1 earthquake hit the San Francisco-Oakland area on?

Group: October 17th, 1989.

Bob Petrella: Tuesday.]

People with HSAM - and there are still only 56 known cases -- remember virtually every day of their lives the way we remember yesterday.

[Lesley Stahl: What day of the week was August 29th, 2005?

Group: Monday.

Lesley Stahl: You all know that? Does it ever freak anybody out?

Bob Petrella: People misunderstand it a lot of times. They think it's photographic. They think it's autistic.

Lesley Stahl: Yeah-- (others nod)

Bob Petrella: --call you Rain Man.

Marilu Henner: Right.

Bob Petrella: And I'll just go along with that. "Yeah, yeah. Definitely Friday." (laughter) ]

The mystery is they're not autistic. They lead normal lives. But Dr. McGaugh says the one thing they have in common is obsessiveness. Just look at Marilu Henner's closet.

Marilu Henner: I like my shoes a certain way - right shoe going this way, left shoe going that way and I have the exact same hangers because then everything slides more easily...

And Bob has a few obsessions of his own -- if he drops his keys on the ground, he feels compelled to wash them. But McGaugh says Bob is the only subject he knows of who has used his extraordinary memory to create a fantasy world.

Dr. James McGaugh: I guess you could say the fantasy basketball team is another form of obsession. But, you know, we use the word "obsession," as being, oh, that's terrible. This person is obsessive. Well, that's not all bad. In some sense it's a good idea to avoid germs. In some sense, it's a good idea to have imaginary basketball team 'cause it doesn't cost anything and it's a lotta fun.

The fun started more than 50 years ago when Bob was in junior high, and a devoted fan of his local high school football team in Beaver Falls, Pennsylvania. They had gone undefeated for two full seasons. So when they finally lost, Bob was devastated. His solution: create a fictional town with its own team -- and run around acting out the games.

Bob Petrella: Once my neighbor's goin', "What is Bobby Petrella doin'?"

Lesley Stahl: Yeah. What are you doing?

Bob Petrella: They would just see me out in the backyard like throwing a football and catching it. And then I would narrate the game and that was Tigertown High School.

The next year, Bob gave his imaginary town, Tigertown, an imaginary college, Holland -- with a basketball team that's been playing ever since.

Lesley Stahl: How does it work? You have a new team every year?

Bob Petrella: Yeah, it's just like college. When they're seniors, they graduate, so we bring in new classes.

Lesley Stahl: Oh, every--

Bob Petrella: Which is always kinda fun for me because it's kinda like having a new kid or something.

He brings them to life as a novelist would -- with personalities, back stories, and colorful names, like Neil Bo Jagger, Travis Shakespeare, Lamar Mundane, and Slappy Hill. Though Slappy wasn't actually his real name.

Bob Petrella: Slappy Hill's real name was Sean. He became Slappy 'cause when he was a little kid, he would-- he was-- he would run around the room and he'd go over and he'd slap everybody's thigh and everybody started callin' him Slappy.

Another favorite, 350-pound center Isaac Moseley, who played in the late 80s.

Bob Petrella: Very nice guy, very gregarious, had a real deep, booming voice. And his name was Isaac Abraham Moseley so he's called, "Big Mo," and he'd walk in. He'd go, "Big Mo is ready for the big show." You know, so it'd echo, "Big Mo is ready for the big show."

Lesley Stahl: This is in your head?

Bob Petrella: Yes. His initials were IAM so whenever someone would ask him something they'd say, "Isaac, how you doin'?" He'd use IAM -- "I am." And he'd go, "I am delighted," you know?

Lesley Stahl: I cannot believe how elaborate that story is. Are they all like that?

Bob Petrella: Most of them.

In real life, Bob is 64, a bachelor and a freelance TV producer in L.A. but unlike a TV writer or novelist, Bob doesn't write his Holland stories down - with his memory he doesn't have to. But he does record each player's stats and has for half a century. And he continues developing life stories for each player after they graduate.

Bobby Simmons: Bob is covering people from the time they get into this school and a little bit before, to when they die.

Bobby Simmons, Nancy Oey, and Mark O'Keefe are among the handful of close friends Bob has let in on his Holland College world.

Bobby Simmons: And he'll send me an email and say, "Travis Shakespeare died in a one-car accident on an icy road outside of Philadelphia," and it's heartbreaking. You know, it's like, oh no. Like, I loved this guy and he's gone.

Lesley Stahl: Are you caught up with Holland College?

Bobby Simmons: Deeply.

Lesley Stahl: Really?

Bobby Simmons: Oh yeah.

We caught up with them at a sports bar during halftime of a Steelers game -- talking Holland.

Nancy Oey: Any controversy with this season at all?

Bob Petrella: No, not yet.

Nancy Oey: Okay, not yet?

Bob Petrella: New coach.

Nancy Oey: It's a new coach?

Mark O'Keefe: Who's the coach?

Bob Petrella: Bradley Hawthorne. And it was a no-brainer that he was gonna take over. Some people thought he should have been hired five years ago 'cause they didn't think that McIntyre was the best--

Mark O'Keefe: So what happened to McIntyre? What's he doin' now?

Bob Petrella: He had osteoporosis and had to retire.

Nancy Oey: Oh.

Bobby Simmons: Wow.

Bob Petrella: It's not funny-- it's a serious disease.

Lesley Stahl: Here's what's weird, the three of you are also into this and accepting the reality of it.

Bobby Simmons: I think that goes to what a good storyteller Bob is.

Nancy Oey: Yes.

Bobby Simmons: And he does it without a pen or without a typewriter or without a computer. He does it in his head. It's amazing.

Bob Petrella: Uhlomi Holobi -- and his first two letters of his name was U-H and H-O. So whenever he would block a shot or have a great play, they'd go, "Uh-oh."

But how do we know as he spins these tales that he isn't just making it all up on the spot?

Dr. James McGaugh: You and I can make up names for a basketball team right now. But I doubt that we would remember them six months from now.

So Dr. McGaugh devised a Holland College memory test for Bob--

Dr. James McGaugh: What year is he?

Bob Petrella: He's a junior.

Hundreds of questions about different players and seasons.

[Dr. James McGaugh: What'd you think about the '89 team?

Bob Petrella: Well, they started off real slow. They were, like, 8-8.]

He then invited Bob back six months later and without warning, asked the same questions again.

[Bob Petrella: They were struggling. They were a .500 team. They were, like, 8-8.]

Dr. James McGaugh: It was seamless, and he just remembers everything about it.

Lesley Stahl: Were there any questions he couldn't answer?

Dr. James McGaugh: No.

Bob Petrella: The main players were Wally White--

Dr. James McGaugh: And how tall was he?

Bob Petrella: He was 6', but he could dunk.

Dr. James McGaugh: Was he tall?

Bob Petrella: No. He's only six foot but he could dunk.

It's hard to fathom the seemingly limitless storage capacity of Bob's brain. So what is Bob's creative process? Does he just sit down and imagine the games in his head? Not even close.

Bob Petrella [as announcer, from afar]: And now for your Holland College Golden Knights!

Bob acts them out--

Bob Petrella: At forward, a 6'9 senior--

--As he demonstrated for us in this real arena.

Bob Petrella: From Detroit, Michigan, Demar Harvey! [spins]

Starting with the player introductions.

Lesley Stahl: Oh my God

.

Bob Petrella: And the coach of the Holland College Golden Knights, in his first season, Bradley Hawthorne.

Lesley Stahl: Are you being the coach?

Bob Petrella (courtside): Yeah. He'll be running-- "And Bradley Hawthorne is not-- not happy." "Well, he shouldn't be happy. That was a bad call on him."

In case you're wondering, those last two voices were long-time announcer Bill Tronzo, and color commentator Adonis McReynolds.

Lesley Stahl: You're both the announcer, and the player, and the crowd?

Bob Petrella: Right.

Lesley Stahl: And you're all the players?

Bob Petrella: Yeah. So, I'm playing about 5,500 people. At once.

But he doesn't actually play them here.

[Bob Petrella (Duke game): Wyatt Hickok at the top o' the key, Wyatt Hickok!]

He plays them in his living room, in real time. This game is against Duke. Bob says he doesn't know who'll win until he plays the game. But either way, he'll remember the outcome forever.

Lesley Stahl: Is there any madness here?

Dr. James McGaugh: I don't think so.

[Bob Petrella (Duke game): And Ladarius Morgan comes up with a steal!]

Dr. James McGaugh: This is a Walter Mitty-type of existence that he has created for himself, except that he knows that he has created it for himself.

Lesley Stahl: You know, children fantasize; little kids.You see them talking to themselves the way he does and creating worlds.

Dr. James McGaugh: Yes. He has his imaginary playmates and they are all basketball players.

Dr. James McGaugh: What happens when they lose? I mean, you must be heartbroken?

Bob Petrella: It depresses the Tigertown population more than me. They don't have as much to live for. They're in a Rust Belt city. They lost a lot of population, a lot of the factories closed. So obviously that means more to them than it does to me. I have to stop myself 'cause I start thinking what I'm saying.

Lesley Stahl: Sometimes when you tell the stories, you smile as if you know that it's funny.

Bob Petrella: Well, I know it's funny. I smile because I'm telling this story. And then I catch myself and go, "Wait a minute. That's not real."

So is Bob like a novelist who creates a whole universe -- a Holland College Hogwarts? Well there are no wizards at Holland but there is a mascot.

Bob Petrella: Well, it's just-- some, you know, like, Trojan type of person. It's-- he's a knight.

Dr. James McGaugh: Do you see it?

Bob Petrella: I don't like it.

Dr. James McGaugh: But you do see it, though?

Bob Petrella: Yeah. I see it.

Dr. James McGaugh: Can't you get that changed?

Bob Petrella: I'm Bob Petrella. I live in L.A. I have nothing to do with it.

Lesley Stahl: I'm intrigued with how he tricks himself into thinking he's not the god of this place, that he's not in control of the events in his own story.

Dr. James McGaugh: It's a narrative that he created. And once it's created, he can't alter it. That's set.

[Bob Petrella (Duke game): And that's it. Holland has beaten Duke.]

Dr. James McGaugh: It is so interesting what he can do because Bob Petrella has a life. He has a job. He gets along well. And then he has this imaginary basketball team and he carries that all in his head.

Lesley Stahl: It's a big part of your life.

Bob Petrella: Oh yeah. Well it doesn't dominate my life, but it's always there.

Lesley Stahl: Could you live without it?

Bob Petrella: I don't think I can anymore. It's not hurting anybody, including me. You know, it's a nice addiction that's safe.

[Bob Petrella (courtside): And then the crowd goes crazy.]