1987 film by John Carpenter
Prince of Darkness is a 1987 American supernatural horror film, written, co-scored and directed by John Carpenter, and starring Donald Pleasence, Victor Wong, Jameson Parker, and Lisa Blount. The second installment in what Carpenter calls his "Apocalypse Trilogy"—which began with The Thing (1982) and concludes with In the Mouth of Madness (1994)—the film follows a group of quantum physics students in Los Angeles who are asked to assist a Catholic priest in investigating an ancient cylinder of liquid discovered in a monastery, which they come to find is a sentient, liquid embodiment of Satan.
Plot summary adapted from Wikipedia, licensed under CC BY-SA 4.0.