There are plenty of reasons to make a movie sequel, but there’s really just one that matters to a Hollywood studio: Money. If a film was a hit, and there’s an opportunity to make more money with a second, a studio is going to take it.

Some movies come with ready-made sequels. A movie about a brave police detective who solves a particularly complicated case? She can go solve another case. A war between humans and aliens for control of a planet and its rich natural resources? Wars can stretch on for years or decades! A superhero defeats a dastardly villain? They don’t call it a never-ending battle for truth, justice, and the American way for nothing.

Ah, but Hollywood doesn’t care if a movie comes with ready-made sequels. If it’s a hit, it’s going to get a sequel one way or another. (Conversely, if it’s a flop, it doesn’t matter if the film ended on a cliffhanger teeing up the next installment in the franchise; it’s not gonna happen. Just ask the folks who made Green Lantern.) In a few cases, a great movie spawned a bunch of sequels so underwhelming they tarnished the reputation of the original film — like the 15 titles below.

Note that I only included franchises that generated at least two sequels. There’s a fair number of excellent films that spawned one sequel that was so bad the studio immediately went “Nope! Our bad! That was a mistake!” They learned their lesson the first time. (Speed and The Odd Couple are two examples that come immediately to mind.)

No, to qualify for this list, a series’ stewards had to doggedly refuse to learn any lessons on multiple occasions. It’s like the Spaceballs sequel they never made (until, uh, now): It’s all about the search for more money.

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