Nelson: {The ingredients were: fresh pureed tomatoes,

Nelson: {The ingredients were: fresh pureed tomatoes, water, salt, and
sodium benzoate used to retard spoilage. Once again, if I'm
not mistaken, this can contained tomato paste.}
Edna: {Thank you, Nelson. I look forward to seeing it again next
week.} Bart, you're up.
[Bart walks up as a cardboard box follows him]
Bart: Boys and girls, Mrs. Krabappel, I come before you today to
solve a riddle that has plagued mankind for centuries: What
has four legs and ticks?
Milhouse: A walking clock?
Nelson: A walking clock!
Martin: I'd wager he has some variety of walking clock in that box!
Edna: Bart, is it a walking clock?
Bart: [mystified] What? No, it's my dog.
-- That was my next guess,
"Sweet Seymour Skinner's Baadasssss Song"