When Dorene throws away Lois' brownies, worried about non-existent peanut allergies, look closely and you'll see a concession stand with big letters spelling out "Peanuts."
When Malcolm offers a hamburger to crying Caroline, she wolfs down 2/3 of it, but after several shots it only has 2 nibbles out of it.
When Stevie is setting up his project, you can see his wheelchair is tied to the table. Two shots later, the rope is gone!
In "Forwards Backwards," it said that Lois is allergic to nuts. If that is so, how was she able to make the almond brownie?
When the Krelboynes made a run for it after Stevie's project exploded, a camara man can be seen chasing after Malcolm for a shot.
When Hal opens his cooler, the sausages are on the right. The next time he opens it, it's gone!
When the Krelboynes were sitting around the picnic table waiting, a camara man can be seen taking shots from underneath the table.
Malcolm: In the wrong hands, these chemicals could make a pretty powerful stink bomb. These hands look wrong enough.
Francis: Hey, Malcolm, how many fingers am I holding up?
Malcolm: Shut up!
Reese: Analyze what I had for lunch! (burps into Malcolm's face while everyone laughs)
Lois: What I can't understand is how you can remember all thoses numbers, but you still forget to brush your teeth! (everyone laughs again)
Hal: Who's up for Burger Barn?
(everyone cheers while the family drives off)
Reese: A small pack of Krelboynes has ventured out of hiding to bask in the afternoon sun. Their defenses down, they are an easy target for nearby predators. They sense danger, it is too late! Their hesitation is fatal! Raahhhhhh!!!! (starts running after the Krelboynes while they start fleeing)
(part of the original cold opener)
Malcolm: Leave the squirrel alone and get the fire extinguisher! Reese, no!
Dewey: Blood tastes funny.
Malcolm: Apparently, the difference between a stink bomb and a Level 3 toxic biohazard is two extra drops of sulfur tetraoxide. I am totally suing that Web site.
(after Dorene argues at Lois)
Hal: Ha, such a nice lady.
Lois: Yeah, tomorrow, we're going shopping for some shoes.
Dewey: Is Malcolm a robot?
Hal: (sighs) No, son. He's just very, very, very, very, very smart.
Lois: Poor baby.
Malcolm: (fake barfing) Yeah, I'm sick.
Lois: No. You're grounded. For pouring perfectly good vegetable soup in the toilet.
Malcolm: (about Malcolm's class picnic) There won't be any meat. They all decided they didn't want to eat anything that has a mother.
Dewey: Cousin Nancy doesn't have a mother.
Lois: That's right. She has two daddies.
Reese: Two guys as your parents? That house has to be a dude's paradise.
Cold Open: Lois and Hal are asleep and in another room. We hear the boys making a lot of crashing noises.
This episode marks the first appearances of Dabney and Lloyd.
Eraserhead: "Kafkaesque, isn't it?"
"Kafkaesque" is an eponym used to describe concepts, situations, and ideas which are reminiscent of the literary work of the Austro-Hungarian writer Franz Kafka, particularly his novels The Trial and The Castle, and the novella The Metamorphosis. The term, which is quite fluid in definition, has also been described as "marked by a senseless, disorienting, often menacing complexity.