Peanuts by Charles Schulz for December 10, 1966
Transcript:
Linus asks, "What's this board for?" Lucy replies, "That's not a board . . . it's a trap door."<BR><BR> Lucy continues, "If you lift that trap door you'll find a long stairway going down fourteen flights and leading to huge storerooms filled with all sorts of candy . . . "<BR><BR> Linus lifts up the board.<BR><BR> Linus says, "You're putting me on!"<BR><BR>
And if you look on the underside of the “door,” you will find the word, “Gullible.”