There is a movie called "Patient 7" that has a part in it exactly like this. Guy carries a body around on Halloween. Meets up with 3 party goers and a girl. He then kills them. Cop shows up, but doesn't do anything. I know this is a remake, but I'm wondering if Patient 7 ripped it off in 2016...either way. Decent movie with decent acting. Like others' said, the first half was promising, not so much the second. Still an enjoyable watch.
Review of The Body
