Here's another film that will take you right back to childhood if you're of a certain age - 'The Princess Bride.' Memorably, it had professional wrestler Andre the Giant in it, but it also starred Wallace Shawn as Vizzini. In fact, it's probably the only Shawn film we can name without having to check Wikipedia - and yet he would never have been in it at all if Danny Devito had been available.
Being the second choice for the only major part of your career would sting the ego of most actors, but Shawn has shown that he's got a sense of humor about it. In an interview with 'Entertainment Weekly,' he said that he was once at the same party as Devito. He accosted the famous actor, and thanked him for having such a busy schedule that it allowed for Shawn to step in and have a moment in the spotlight. Devito, apparently unsure of the best way to respond to this, laughed and walked away. Perhaps he didn't even know who Shawn was!