Erez Eisen was born on 8 September 1980 in Kiryat Yam (Hebrew: קִרְיַת יָם‎‎, lit. Sea Town), Israel. He had early musical training, learning to play the organ at age 4 and studying piano in the Haifa Conservatory from the age of 8. At age 11 he started toying with computerized music, first using Impulse Tracker and later moving to more advanced musical composition software. By the age of 18, Erez had collaborated with DJ Jörg and other notable psy-trance artists,and had released three albums and a multitude of tracks under different psy-trance acts (including Shidapu and Shiva Shidapu).

In 1998, Eisen and Amit Duvdevani began playing together. At first they released a few tracks as Shidapu & Duvdev. These tracks were 'happier' and of the simpler side of trance. Later on, they formed the duo Infected Mushroom and started working on their first album.