Michael Keaton as Beetlejuice and Six Other Roles and Their Irreplaceable Actors

When I heard the recent news that a Beetlejuice sequel was underway, I felt a little uneasy. Money is driving Hollywood more than ever these days and sequels are often seen as another uninspired attempt to cash in. However, the screenwriters behind the project, David Katzenberg and Seth Grahame-Smith, appear to be men of honor as they won't do the project without Tim Burton's blessing or Michael Keaton in a starring role. Bravo, gentlemen. They've gotten Burton's blessing, and as soon as they've got a finished script to pitch, they plan to show it to Keaton.

Here are six other actors and the roles in which they're irreplaceable.

Johnny Depp as Captain Jack Sparrow

Something tells me that the Pirates of the Caribbean movies are going to continue long after Depp steps down. But what's the point? Jack Sparrow is the Pirate of the Caribbean. Now, I didn't much care for the third film and I thought the second was garbage, but at the very least, you had Johnny Depp at his best. There'll be other pirates, but there will never be another Captain Jack.

Arnold Schwarzenegger as The T-800/T-850/T-101

There have been many "terminators" in the film franchise and the television series, but none as iconic as Arnold. Even though he's technically a different terminator in each of his appearances, with that ruggedly handsome face and that lovable Austrian accent, he's always the same character in our hearts.

Jim Carrey as Ace Ventura

Come back to comedy, Jim. Don't get me wrong, you're a great dramatic actor. Eternal Sunshine of the Spotless Mind is one of the best films ever made, thanks in no small part to your performance, but comedy needs you. Hell, you're not just irreplaceable as Ace Ventura, you're irreplaceable in comedy as a whole. You left a hole, Jim. A rubbery, goofy hole.

John Heder as Napoleon Dynamite

Say what you will about Napoleon Dynamite but gosh, that's Heder's role. Unfortunately, I'm not a big fan of Heder outside of that role, but he sure made Napoleon someone memorable. Sure, it's been ground into a fine paste over the years through overexposure - it's one of those films that hipsters clung to even though it was fairly popular in the general spectrum - but damn it, it's still funny.

Christopher Lloyd as Doc Emmett Brown

You could argue that Michael J. Fox is just as irreplaceable in his role as Marty McFly, but you'd be wrong. I love Fox and to see anyone else as Marty would break my heart, but I'd have an easier time accepting that then someone other than Lloyd playing Doc. With his wacky mannerisms, his great scotts, and his gigawatts, nobody could bring Doc Brown to life like Christopher Llyod did.

Harrison Ford as Indiana Jones/Han Solo

This is a bit of an odd one. Everyone on this list is irreplaceable thanks to their eccentricities, but Ford plays it straight. And yet, he's shaped Solo and Dr. Jones so uniquely that he could never be replaced. He has just the right amount of indifference and charm, a perfect storm of roguishness, if you will.

There are undoubtedly more actors that belong on this list, but great scott, these are the ones that came to mind.