Breakthrough roles tend to reduce an actor to typecasting, but after seeing the “The Guest” it’s impossible to ever again see Dan Stevens as nice Cousin Matthew from “Downton Abbey.” As a mysterious probable-psycho who shows up at the home of a Midwestern family, claiming to have been friends with their late soldier son, Stevens is confident in a way that’s both chilling and charismatic — a guy you know is no trouble but who you’re drawn to anyway. Many of the characters in Adam Wingard’s indie thriller fall under his sway; most of those meet unpleasant ends. But even when Stevens’ character has gone full baddie, it’s impossible not to root a little for him anyway. “The Guest” has more going for it than Dan Stevens. Wingard’s direction borrows from the Nicolas Winding Refn mix of confident shots and ’80s synth music. But at its best it’s as seductive as its star, who if he’s going to be typecast should be typecast as this.