What's the worst final act to an otherwise good film that that you've ever seen?

Just finished Spiderhead on Netflix. The first 2/3rds are an enjoyable, tense, big-budget Hollywood Thriller. The final third was like a completely different movie, shifting completely into attempted Marvel Comedy territory, and not in a good way. I was shaking my head, wondering if somebody had put a different movie on.Got me thinking, what are some other movies that you enjoyed and thought were good, only for the final act to go off the rails? via /r/movies https://ift.tt/EGVOZvI