6. Aliens Vs. Predator: Requiem
It's been over a decade now since Aliens vs. Predator: Requiem was unleashed, and time has not been kind to it. After Alien vs. Predator's moderate financial success in 2004 reinvigorated both dormant Alien and Predator franchises by mashing them together, Requiem swooped in to try and keep the ball rolling, only to stumble and break the budding crossover franchise's neck in the process.
Whereas its predecessor had a PG-13 rating, Requiem hit theaters with an R and the promise that the ante would be upped in terms of gore and overall action, but somehow it managed to toss it all down the drain, resulting in a product that's boring at best, ugly to look at, and filled with characters even more forgettable than the movie itself. Even the Predalien, the intriguing hybrid of the two species that pops up at the very last second of the previous movie, feels like a complete waste, while the standard Predator and Aliens lining the film don't carry any weight.
Requiem killed the Alien vs. Predator franchise before it ever really took off, something that allowed the standalone franchises to start anew a few years later with 2010's Predators and 2012's Prometheus, and of all the films that feature either or both of the two iconic creatures, Requiem is far and away the worst of the bunch, offering nothing new to the overall mythology while feeling like a colossal waste of an otherwise fun concept.