X + YY: Formel des Bösen
- Curs: 1970
- País: Germany
- Gènere: Crime, Thriller
- Estudi: Brünnstein-Film
- Paraula clau: exploitation, playboy, serial killer, hormones
- Director: Teja Piegeler, Pavle Jovic
- Repartiment: Ljubiša Samardžić, Kai Fischer, Miloje 'Mića' Orlović, Albert Hehn, Leonina Pavlović, Stefan Zessner