The superb opening credits to director and author Fernando Arrabal’s 1971 masterpiece, Viva la Muerte (Long live death). The awesome song is called “Ekkoleg,” written and produced by Grethe Agatz .

Arrabal was a part of the Panic Movement in the 1960s. which also include El Topo and Holy Mountain director, Alejandro Jodorowsky. The animation was done by Roland Topor, another member of the Panic Movement.
 

 
Thank you Chris Campion of Berlin, Germany! Via Easydreamer blog.