The first word in the title of Pere Portabella’s ravishing 1970 underground masterpiece, made in Spain while General Francisco Franco was still in power and shown clandestinely, means both “worm’s tail” and the unexposed footage at the end of film reels. The film is a silent black-and-white documentary about the shooting of Jesus Franco’s Count Dracula, with Christopher Lee, that becomes much more: the lush, high-contrast cinematography evokes deteriorating prints of Nosferatu and Vampyr, and the extraordinary sound track by composer Carles Santos intersperses the sounds of jet planes, drills, syrupy Muzak, and sinister electronic music, all of which ingeniously locate Dracula and our perceptions of him in the contemporary world. Moving back and forth between Franco’s film (with Dracula as an implicit stand-in for the generalissimo) and poetic production details, Portabella offers witty reflections on the powerful monopolies of both dictators and commercial cinema. The only words heard are in English, spoken by Lee and written by Bram Stoker. 75 min. Reviewed this week in Section 1. a Sat 11/11, 5 PM, and Wed 11/15, 8 PM, Gene Siskel Film Center. I will introduce the Wednesday screening and lecture on Portabella afterward.