You probably knew that the immediately outdated 2002 horror movie The Ring was based on the slightly more technologically plausible and infinitely better reviewed 1998 Japanese film Ringu.
Still, everything makes a lot more sense when you realize that was based on a 1991 novel that spawned a labyrinth or sequels ... right until it doesn't. The first movie more or less follows the events of the first book installment, but if you thought supernatural deer attacks were crazytown, you are not prepared for a virus transmitted via videotape.
Yep, it's revealed in the second novel of the Ring series that what actually kills people when they watch the tape is a virus that causes the fastest-growing tumors ever, and it follows the coroner's attempts to stop it. But all of that is blown away by the third novel, where it's revealed that everything that happened in the previous two books took place inside a simulated reality built by a group of scientists to virtually recreate the emergence and evolution of life.
Through a series of increasingly dubious events, one of the characters living inside the simulation gets cloned into reality, taking the virus, which mutates into a deadly form of cancer, with them. The only way to stop it, as the man investigating the simulation (who turns out to be the cloned man, which is why he is immune to the cancer) learns, is for him to permanently enter the simulation so his body can be digitally analyzed. This was supposed to be the end of the series, but several more short stories and novels followed, although what more could you want at that point?
Other than a change of underwear.
Top image: DreamWorks Pictures