Mac believes that he created a new imaginary friend named Cheese in his sleep, which makes Bloo jealous and eventually driven insane.
This episode provides examples of:
- Annoying Background Event: Mac and Bloo discuss what to do about Cheese, while Cheese is playing with a toy horse just off frame. Eventually, Bloo gets sick of Cheese's horse and yells at him to cut it out.
- Annoying Younger Sibling: Cheese acts like this to Bloo in his debut, annoying him with his idiocy, but he turns out not to be Bloo's brother when it's revealed that he is Louise's imaginary friend.
- Annoyingly Repetitive Child: Cheese is the imaginary friend of Louise, and he has a child-like personality, often irritating others. In this episode, he squeals "Whee!" for what is implied to be for hours when he rides Mac and Bloo's soapbox car down the hill on Mulberry lane very slowly. He also keeps saying "I like cereal." and "Cocoa!", much to the respective dismays of Eduardo and Coco.
- Big Brother Instinct: Despite starting on the wrong foot with him, Bloo exhibites this side to the less-than-mentally-stable Cheese after realizing how much risk he'd be taking by letting the poor little dude walk independently. Then he reverts back to hating him by the end when he and his owner reunite, realizing that he already has someone to keep him in line.
- Cloudcuckoolander: Cheese, full stop.
- Elderly Future Fantasy: When Mac has Cheese stay at Foster's with Bloo, Bloo is horrified at the aspect of him and Cheese staying at Foster's together forever. One of the nightmares Bloo has depicts him and Mac as old men sitting in rocking chairs as an equally-elderly Cheese says "Look what I made!" and shows them a telephone with a sock taped to it.
- Fully Automatic Clip Show: The Stinger depicts all the times that Cheese says "I like cereal!" and "I like chocolate milk!" in the episode. It's played twice, the first time ending with Cheese saying "Do it again!", and the second time ending with Eduardo saying "I like potatoes." and Cheese saying "Yeah, I like potatoes."
- Heterosexual Life-Partners: Mac and Bloo, which is particularly funny in this episode, when they discuss Mac's creation of Cheese as if Mac cheated on Bloo.
- Hot Paint Job: Bloo wants to paint Mac's soapbox car in hot-rod flames, but Cheese wants bunnies instead. After much arguing, they compromise and paint flaming bunnies on the car.Bloo: I don't even know you anymore.
Mac: Shut up. At least the bunnies are on fire. - Hug and Comment:Bloo: I love you, brother! (hugs Cheese)
Cheese: I pooted. - Ironic Allergy: Despite being named after a dairy product and liking chocolate milk, Cheese is lactose-intolerant.
- Irritation Nightmare: Bloo has a nightmare involving a crossdressing Cheese ruining a fantasy moment saying, "I'm a lady!", then kissing Bloo and saying, "Now we're brother ladies!"
- Lame Pun Reaction: Done several times: Mac and Cheese, Bloo Cheese, and finally "Cheese Louise". Cue Mac's Face Palm.
- Parental Bonus: Mac waking up next to Cheese and having to explain his "mistake" to Bloo is played a lot like marital infidelity.
- Punny Name: A variant; cheese puns are invoked whenever Cheese is paired with someone. "Mac and Cheese", "Bloo Cheese", "Cheese and Crackers", and "Cheese Louise" are mentioned.
