Having a threesome is the classic male fantasy - but over the years pop culture has shown us the oh-so-many ways that it can wind up being a disaster. It seems that Eli Roth's new film Knock Knock is yet another example of one of these ways, but rather than being a drama about hurt feelings, it appears this one is a strange up horror show. As you can probably tell, this preview debuted over on director Eli Roth's personal Facebook page - and it's honestly a rather strange trailer. After all, it does a solid job of setting up the film's initial action - Evan Webber (Keanu Reeves) is home alone and basically gets seduced into having a threesome with two lovely ladies (Ana de Armas, Lorenza Izzo) - but it doesn't actually demonstrate any of the negative consequences that are going to be on display. Yes, obviously Reeves is doing something morally wrong by cheating on his wife, but what exactly can we expect to see as his horrific punishment? As things stand, all we really have are a few ominous title cards and a stern-looking Reeves walking down a hallway while women giggle in the background.