Celtic Frost () were a Swiss extreme metal band from Zürich. They are known for their strong influence on the development of extreme metal and avant-garde metal. Formed in 1981 as Hellhammer, the band became Celtic Frost in 1984 and released their debut, "Morbid Tales", that year. This was followed by "To Mega Therion" (1985) and the highly experimental "Into the Pandemonium" (1987), all of which were widely praised. Their next album "Cold Lake" (1988) saw a new lineup and a radical change of style, which was widely derided. After the release of "Vanity/Nemesis" (1990), the group disbanded. It re-formed in 2001 and released the critically acclaimed "Monotheist" (2006), before disbanding following frontman Tom Gabriel Fischer's departure in 2008.