Gillian Flynn's The Grownup is one of the funniest dark-comedy-horror-thriller stories I've ever read. Also, I'm not sure I've ever read something so short that intersected so many genres so seamlessly.

With the main (protagonist?) character and everyone else playing the unreliable narrator, by the end of the tale every turn of the page provided a new twist and re-evaluation of past events. Just as a talented con artist plays on people's assumptions, so too does this narrative with the stereotypical tropes of the horror and thriller genres.

Anyway you may view the ending, it's great. If you have a dark sense of humor or like any of Flynn's other work do yourself a favor and just read this one.