I know the producers of the Stargate franchise also produced this series first, but the creature looked like a transparent/translucent Gou'ald, at the end of the 5th season of Stargate: SG-1 they introduced an evil Gou'ald named Anubis who had tried to ascend like the Ancients in that series and they were transparent/translucent beings.
It's also interesting David Warner played a time traveler being pursued by H.G. Wells in the movie "Time After Time" (1979) and his character John Leslie Stevenson was also Jack the Ripper.