Freaky is basically a twist on "Freaky Friday", which stars Kathryn Newton as a High School student and Vince Vaughn as a Psycho Serial Killer. Vaughn's character is trying to kill Newton with a special dagger and when he stabs her they end up switching places were Newton is now the crazed killer and Vaughn is now the HS girl.
The plot although not completely original, is very original in the sense that I've never seen a film quite like it. Only other similar film would be "Face Off" but this is more of a Horror Comedy vs an Action film. I really did dig it quite a bit and it is one that I will definitely buy for my personal Collection. I highly recommend!