Nostalgic obsession is a funny business. One man’s undying childhood passion is another man’s baffled “Hunh?” And hearing the name The Rock-afire Explosion will probably elicit a massive, collective “Hunh?” But to some people who grew up in the American south in the ’80s, the name evokes a rapturous beatification.

For those not in the know, the Rock-afire Explosion was an anthropomorphic animatronic band that performed at the Showbiz Pizza Place. An early competitor to Chuck E. Cheese, Showbiz had the same formula: A kid-oriented dive that had video and arcade games and a cheezy stage show where robotic animals played music and performed comedy skits. But where Chuck E. Cheese’s “band” was limited, the Rock-afire Explosion had a large cast and Disney-quality animatronic performers.

As someone who’s been to a Chuck E. Cheese once or twice in his life and someone who’s now watched Brett Whitcomb’s eponymously titled documentary about the fans and creator of the Rock-afire Explosion I still have to say: I don’t get it. I could not tell you what it is about this goofy childhood entertainment that has instilled such a passion in this group of now-adults. Actually, “rapturous beatification” isn’t a strong enough phrase to describe the passion on display in this film.

However,, it doesn’t really matter if I, or anyone else, “gets it” by the film’s conclusion. This is still a hugely endearing and heartwarming documentary.

Rather than portray his subjects as just a collection of oddballs and misfits — and most of them seem to know how extraordinarily strange their obsession might seem to the rest of the world — Whitcomb treats them all with the utmost respect and compassion. You want to see what they see in the Rock-afire Explosion since it’s such an innocent joy and love that they feel.

Although several Rock-afire Explosion fans appear in the film, there are really two main characters. The second most important star of the film is Aaron Fechter, the Rock-afire Explosion’s creator. It’s tough to tell how old Aaron is now, but he looks like a guy who had two career choices in life: Beach bum or inventor. He went the inventor route and initially became involved making targets for carnival shooting galleries, which eventually led to him creating the Rock-afire Explosion for Showbiz Pizza Place.

At its peak, Showbiz owned 200 restaurants across the south and almost as soon as they opened that 200th store, the company realized it couldn’t turn a profit with their animatronic main attraction in place. In a bold and ultimately costly move, Fechter in a show of loyalty to his beloved creation went his own way rather than completely selling out. (His company, Creative Engineering, owned the rights to the Rock-afire Explosion characters.) While he had plans to move the Rock-afire Explosion into other media without Showbiz, interest in the concept petered out when they stopped performing for the public.

But the Rock-afire Explosion didn’t die completely — at least in a couple kids’ hearts. The real star of Whitcomb’s documentary is Chris Thrash, arguably the Rock-afire Explosion’s biggest fan. Professionally, a DJ at a skating rink, Thrash says that he worked many additional odd jobs for two full years to earn enough money to buy his own Rock-afire Explosion that he could set up in the garage behind his house, which is exactly what he did.

Thrash is a sincere and a compassionate man. He lets the neighborhood kids come over and watch the Rock-afire Explosion perform in his garage for free because, as he says, he just wants them to have the same good feelings he had as a child. He seems so wrapped up in his obsession that, just as soon as you start to wonder if he’s married or not, we’re introduced to his shy wife whom he met, proposed to and married at the skating rink. Their story is so innocent it’s impossibly touching.

Ultimately, the film isn’t just about the Rock-afire Explosion or the people who continue to love it. Everyone has their own personal nostalgic touchstone, whether it’s a candy bar, or a comic book or a movie or whatever, which is really what Whitcomb is appealing to here. Give me a stack of ’70s Len Wein-era Mighty Thor comic books and let me spend the day in bed and I’ll be in the same Heaven Thrash is in in his garage. Isn’t that a Heaven we’d all like to be in?

(This film was sent to the Underground Film Journal as a screener from the 2009 Boston Underground Film Festival, which runs this year March 19-26.)

Watch The Rock-afire Explosion movie trailer: