Bruce Spence is in A LOT of movies, but he's in an unusual amount of third movies. By third movies, I mean the third in a series of movies.
After appearing in Mad Max 2: The Road Warrior, he was in the third Mad Max movie, Mad Max Beyond Thunderdome.
He was The Trainman in the third Matrix movie, The Matrix Revolutions.
He was the Mouth of Sauron in the third Lord of the Rings movie, The Return of the King.
He was in Star Wars: Episode III - Revenge of the Sith, which is not the third Star Wars movie made (that, of course, was Return of the Jedi), but still counts because it's called Episode III.
He was in the third Narnia movie, Voyage of the Dawn Treader, too.
As an honorable mention, Bruce Spence was also in the movie The Queen of the Damned. This was only the second film adaptation of Anne Rice's Vampire Chronicles, but the third novel in the trilogy (hence the honorable mention).
Are you aware of any other associations of Bruce Spence and third movies? If you do, let me know in the comments!