10 MORE Horror Movies That Go Totally Insane At The End

As mentioned earlier, a crazy ending can single-handedly keep a movie alive in the cultural consciousness far longer than would've been expected. 

In 1989's Society, high school student Billy (Billy Warlock) discovers that his adoptive parents are part of an elite cult, which perhaps epitomizes a crazy ending that's kept a movie's name alive.

Society isn't a good film. The first hour is sluggishly paced, the acting is uniformly risible, and yet, once the it arrives at the climactic cult meeting, it becomes mesmerizing in its depravity. The things you see here are just deranged. 

The cultists kill a young man by sucking and absorbing his body, members of the group meld into one mass of flesh, the protagonist kills the main villain by sticking his arm up his rear end and pulling him inside out, and, of course, there's the moment where Billy discovers his father has turned himself into a pair of legs with his face where a bottom should be. The father, referring to an earlier insult, exclaims, "Well, son, I guess you're right... I am a butthead!" 

As such, even if most of the movie is pretty poor, such is the icky power of this ending that Society is impossible to disregard completely.