I, Monster is a 1971 British horror film directed by Stephen Weeks (his feature debut) for Amicus Productions. It is an adaptation of Robert Louis Stevenson's The Strange Case of Dr. Jekyll and Mr. Hyde, with the main characters' names changed to Dr. Charles Marlowe and Mr. Edward Blake.
It stars Christopher Lee as the Doctor and his alter ego, and Peter Cushing as Frederick Utterson, a central character in Stevenson's original story. Mike Raven and Susan Jameson also star. It was photographed by Moray Grant, with music by Carl Davis.
It was intended to be shown in 3-D, but the process was aborted mid-filming.

Several old college friends converge at a mansion, ostensibly for a pleasant reunion. Larry Dann, the most easygoing of the bunch, comes to the conclusion that all is not well in the old dark house. For one thing, he's run across several people whom he's never met. For another, they all seem to be of a different time and place.

The medieval legend of a supernatural knight who challenges the king's men to kill him.