Kitty: How can this be happening? Stevie never used to do things like this. He used to be such a good boy. He used to hold my yarn while I knitted. And I would hold his yarn while he knitted.
Abe: He made this sweater.

Reese: What did you hear?
Dewey: Everything. I want to go to the fair.
Malcolm: No, Dewey. You're too young.
Dewey: Take me or I'll tell Mom.
Reese: If you do, I'll just stomp the crap out of you.
Dewey: Go ahead. I'm still telling.
Malcolm: Dewey, you're not going and you're not telling. If you blab to Mom, we'll take every pet you ever get and set it free.
Reese: We'll destroy every toy, every game, everything you ever love.
Dewey: Do what you have to.

Kitty: A sleepover?! At someone else's house?!
Abe: Don't you like sleeping here, son?
Kitty: I don't think this is a good idea, Steve. I mean, Malcolm's family doesn't have a HEPA filter air purifier and God knows how outmoded their alarm system is. They probably don't even have motion detectors.
Abe: Be honest, son. Is it my snoring?
Kitty: You have a perfectly good hypo-allergenic mattress here to sleep on. I just don't see the point.
Stevie: It would help... me feel... normal. [rolls away] Fish... in a barrel.