X + YY: Formel des Bösen
- annos singulos: 1970
- Patriam: Germany
- genus: Crime, Thriller
- Studio: Brünnstein-Film
- keyword: exploitation, playboy, serial killer, hormones
- Director: Pavle Jovic, Teja Piegeler
- cast: Ljubiša Samardžić, Kai Fischer, Miloje 'Mića' Orlović, Albert Hehn, Leonina Pavlović, Stefan Zessner
