I do remember the start of the movie a guy runs from a mob of people he has a tattoo he ran but got caught and they people Shoved something threw his Anus to his mouth and then it went to a different scene with people I also remember the ending were 2 people drove away but the leader of the evil carnies was in the back with a eye patch on and i think he killed them but the screen went black
Sounds like 2001 Maniacs (2005)
Here’s a link to the film on YoutTube:
https://www.youtube.com/watch?v=a583BUoTn5c
Hope this helps.