Laugh box

Squidward: Tell me, SpongeBob, have your sides been hurting?

SpongeBob: Yeah, a little.

Squidward: And your temperature is 175 degrees!

SpongeBob: It's that bad?

Squidward: Oh, no, no, no, no, no, no. Unless you've been doing a lot of laughing.

SpongeBob: I have been laughing a lot, lately.

Squidward: [gasps] SpongeBob, you've got to be careful! You're gonna burn out your laugh box.

SpongeBob: My laugh box?

Squidward: Yes, it's the part of your body that enables laughter. If you use it too long without giving it a break, it burns out and you can never laugh again.