Willhelm von Homburg played the villainous Vigo the Carpathian in Ghostbusters 2. However, although he spoke all the lines while they were shooting, he was dubbed over by Max Von Sydow. Kind of David Prowse and James Earl Jones in Star Wars.
Sadly no one told Willhelm. He only found out when he saw the film at a screening. Needless to say he stormed out in anger.
The video below gives us the opportunity to hear what Willehelm sounded like as Vigo.