The Guest (2014)

Another home invasion film, this one is a little more conspiracy focused and incredibly terrifying. When a young solider appears on the front porch of a grieving soldiers family, and tells them that he was their son’s best friend in Afghanistan, they take him in and let him stay a few days. Then the killings begin.

This one is plausible because who wouldn’t want a comrade of their dead son to come tell them stories about their boy, and who wouldn’t extend hospitality to that guy? It makes sense that they’d warm to him, and the truth behind his visit and his background is pretty crazy, if not kinda true.