David Letterman developed an awesome cottage industry repeatedly tweaking his "Mitt Romney looks like..." joke before the animatronic, amazingly lifelike demagogue dropped out of the race for the Republican presidential nomination earlier this month. But Jon Stewart just won't let the gag die. Speaking to Larry King tonight, Stewart worked in two digs about Romney, one of which actually began with the words "he looks like..." Letterman's ownership of the meme is so complete Stewart will probably have to cut a royalty check tomorrow morning, but it will be so worth it: