Marlin: There was this mollusk, and he walks up to this sea cucumber. Normally, they don't talk, sea cucumbers, but in a joke everyone talks. So the sea mollusk says to the cucumber...
[sees the mask]
Marlin: Nemo!
Chum: [laughing] Nemo! Ha ha! Nemo... I don't get it.
Bruce: For a clown fish, he's not that funny.