Open Sesame/X Marks the Spot (from The Muppet Alphabet Album)

Cast

 * Oscar's Bridge to Reading Book as Sherlock Hemlock
 * Grover's Orange Book as Ernie

Lyrics
Grover's Orange Book: (spoken) Let's see now? What letter comes after W? Gee, to figure that out, I need an alphabet or a dictionary or maybe even a detective.

Oscar's Bridge to Reading Book: (spoken) Egad! Oscar's Bridge to Reading Book here, the worlds greatest detective. And I believe the letter following "W" is... (singing) "X" marks the spot. "X" marks the crossroads. Two straight lines crossing Over in the middle. That's the letter you must see to Find the treasure or the clue, Or the X-ray machine that's Looking right inside of you. "X" is the letter without which One could not do.

"X" marks the spot. "X" stands for danger. Two straight lines crossing Over in the middle Saying "Here's the railroad crossing" And sometimes it means there's pirates Or at worse, it means there's poison And in case these thoughts of "X" Are vexing you "X" stands for "xylophone," too