The scene where Aunt Edna dies during their trip. Especially when they wrap her body up and put it on the roof, and then deposit it at her son's house. Granted, she was an insufferable old bitch, but it's still pretty morbid.
A Deleted Scene shows a Finger Twitching Revival while strapped to the roof, then left at her son's house. Apparently this was left out because it was darker than leaving her corpse outside her son's house.