Caleb: Momma, why does a sea serpent not have legs?
Me: Well, because that's the way God made it.
Caleb: No, Momma. This is a joke.
Me: Oh! Okay, well then, why?
Caleb: It's not a knock-knock joke, Momma.
Me: I didn't say "Who's there."
Caleb: Oh. Okay.
Me: So, why doesn't it have legs?
Caleb: (cracking up) So it can swim!!!!
Caleb: Yeah, I guess it was only a little bit funny.