Bart: Well, if your soul is real, where is it? Milhouse:

Bart: Well, if your soul is real, where is it?
Milhouse: [motions to his chest] It's kind of in here. And when you
sneeze, that's your soul trying to escape. Saying "God bless
you" crams it back in! [gestures up his nose] And when you
die, it squirms out and flies away.
Bart: Uh huh. What if you die in a submarine at the bottom of the
ocean?
Milhouse: Oh, it can swim. It's even got wheels in case you die in the
desert and it has to drive to the cemetery.
Bart: [sighs] Oh, how can someone with glasses that thick be so
stupid? Listen: you don't have a soul, I don't have a soul,
there's no such thing as a soul!
Milhouse: [smug] Fine. If you're so sure about that, why don't you sell
your soul to me?
Bart: [pause] How much you got?
Milhouse: Five bucks.
Bart: Deal.
[writes "Bart Simpson's Soul" on a piece of paper]
There you go: one soul.
Milhouse: [sly] Pleasure doing business with you.
Bart: Any time, chum...p.
-- The transaction thickens, "Bart Sells His Soul"