An Italian prog rock band active throughout the 1970s and 1980s. They are best known (in the circle of horror film buffs, at any rate) for their soundtrack work on a number of Dario Argento's films, including Deep Red and the seminal masterpiece Suspiria. Their music also forms part of the soundtrack from Dawn of the Dead (which Argento worked on as well).
Their music is very dark and rather aggresive, yet subtle. It's not the music of someone clumsily shambling after you with a knife; it's more the sound of some thing from the hinterland of nightmares pursuing you through a dark forest of looming pines and grasping, fingerlike branches.
The band consisted of Tony Tartarini (vocals), Massimo Morante (guitar), Claudio Simonetti (synthesizers), and Walter Martino (drums).