At the beginning of the 1970s, Blažić (at the time playing the drums), vocalist Branko Umković, and three other future members of Atomsko Sklonište, bass guitarist Bruno Langer, guitarist Dragan Gužvan and drummer Saša Dadić, formed the cover band Hush.

[1] The group attracted the attention of the public with their anti-war concept and cataclysmic imagery,[1] and gained large mainstream popularity with the release of their debut album Ne cvikaj, generacijo (Don't Be Afraid, My Generation) in 1978.

[1] The group maintained their popularity with their live performances and following studio albums, scoring a number of hit songs.

[3][5] It consisted of concerts and futsal tournaments, with all the funds raised dedicated to people fighting cancer.

[6] In 2014, a green area in Krležina street in Pula was officially named Poljana Sergio Blažića-Đosera after him.