The Losers’ Club was a big winner last weekend.

Director Andy Muschietti’s adaptation of Stephen King’s 1986 best-seller “It” did in a weekend what only 11 movies all summer could do: Top the vaunted $100 million mark at the box office.

According to the numbers-crunching site Box Office Mojo, “It” scored $123.4 million between Thursday-night previews and the close of business Sunday. That number shattered several records simultaneously, becoming the biggest September opening ever, the biggest fall opening ever, the biggest R-rated movie opening ever and the biggest horror movie (regardless of MPAA rating) ever.

“It” was the third-biggest opening of 2017, beaten only by Disney’s “Beauty and the Beast” ($174.7 million) in March and Marvel’s “Guardians of the Galaxy Vol. 2” ($146.5 million) in May.

And “It” reached this high number without being all the things Hollywood thinks a successful movie should be. It didn’t have a ton of computer effects and action sequences. It didn’t scale back its violence or frights for a PG-13 rating. It didn’t have big stars, unless you think the kid from “Stranger Things” qualifies. And it was made for a measly $35 million, compared with the $150 million and $200 million price tags on most summer blockbusters.

Also, “It” opened with some major markets, like Miami and Tampa, out of commission due to Hurricane Irma.

“It” did have one supposedly bankable name attached to it: the author, Stephen King, whose name is synonymous with horror. But if King were a reliable draw, then “The Dark Tower,” the movie based on his sprawling fantasy series, would have opened with more than $19.2 million in August. In six weeks of release, “The Dark Tower” has made almost $49 million — less than the $60 million it reportedly cost to make and a fraction of what “It” made in a weekend.

(Leah Hogsten | The Salt Lake Tribune) Stephen King reads from his novel, "End of Watch," to a crowd at Juan Diego High School, Friday, June 17, 2016 in Draper.

(In case you missed it, there was an attempt by right-wingers online to mount a boycott of “It” because of the unkind things King has said about Donald Trump. The boycott really seems to have put a damper on ticket sales, hasn’t it?)

Theories abound as to why “It” was a hit. Some point out that it’s been a strong year for horror movies, with “Split,” “Get Out” and “Annabelle: Creation” all topping the weekend charts at different points this year. Joanna Robinson, a writer for Vanity Fair, chalked it up to horror nostalgia, since the kids in “It” inhabit the same 1980s culturescape as the characters of “Stranger Things.”

More likely, it was largely because of King’s name recognition, along with three things “The Dark Tower” didn’t have: a solid marketing campaign that made clear the movie’s scariness, strong word-of-mouth reactions, and positive reviews from critics.

This image released by Warner Bros. Entertainment shows Gal Gadot in a scene from "Wonder Woman." (Clay Enos/Warner Bros. Entertainment via AP)

The summer box office was, says the trade paper Daily Variety, the worst since 2006. The three biggest hits were superhero movies: “Wonder Woman” ($410 million), “Guardians of the Galaxy Vol. 2” ($390 million) and “Spider-Man: Homecoming” ($328 million). Some franchises (“Despicable Me 3,” “Pirates of the Caribbean: Dead Men Tell No Tales,” “War for the Planet of the Apes”) scored well, but others (“Transformers: The Last Knight” and “Alien: Covenant“) underperformed.

Then there were the attempts to turn familiar material into new movie franchises. Movies like “The Mummy” and “Baywatch” cratered, even with big stars (respectively, Tom Cruise and Dwayne Johnson) as leads.

This image released by Universal Pictures shows Regina Hall, from left, Jada Pinkett Smith, Queen Latifah and Tiffany Haddish in a scene from the comedy "Girls Trip." (Michele K. Short/Universal Pictures via AP)

The most leff-field surprise of the summer box office was “Girls Trip,” a bawdy comedy about four African-American women letting their hair down on a weekend in New Orleans. The movie raked in $113 million in a summer when other raunchy comedies — like “Rough Night,” “Baywatch” and “The House” — bombed.

Will Hollywood look at the successes of the summer of 2017 — particularly the ones that point to inclusion, like a female-led superhero movie or a comedy with four African-American women taking center stage — and figure out how to repeat them? Considering the studios’ inability to turn away from old formulas, the odds are against it.