Here's a link to some of the Mets walk-up songs, via MLB.com.
My favorite:
How about the theme for Mighty Mouse?Fernando Tatis, LF
Song: "Theme from 'Superman'" composed and conducted by John Williams
Tatis: "I don't care. I don't even know what it sounds like. Somebody was joking with me. I have no idea. They just put it on and play it."
Critic commentary: "Brag much? Although given the way he's saved the Mets time and again this season, the comparisons to a certain caped crusader are not entirely inappropriate." --Saul Austerlitz, freelance critic for Boston Globe and other publications
