Generally speaking, the whole reason to make a sequel is name recognition. Studio executives don’t bankroll Space Zombies From Beyond the Stars 4 because they believe deeply in the concept of space zombies and have something personal to say about them; they do it because Space Zombies From Beyond the Stars 3: Brain Drain made a lot of money, and they hope another sequel just like it will also make a lot of money. That’s how the system works.

Or at least that’s how it’s supposed to work. Every so often, a sequel emerges from that system that’s a little different than the norm. Maybe it took years or even decades to emerge from development. Maybe it features a totally different cast or creators than its predecessor. If it was a cash grab, well, it wasn’t a particularly clear or effective one.

That’s the case with the 15 titles below, all of which are sequels in some form or another — but are not widely recognized as such by the moviegoing public. A couple of them might have downplayed their true nature for legal reasons. A few were based on flops (or TV shows) with limited audiences (and thus limited numbers of audience members who would know they just bought a ticket to a sequel). A few were made by people who didn’t like the film they were making a sequel to — so they went out of their way to claim their movie was not a sequel at all.

But it was. (Sorry, Jon Favreau.) Here are 15 examples of movies that a lot of viewers don’t realize are sequels.

READ MORE: 20 Movie Sequels You Forgot Existed