Phineas and Ferb Wiki
Phineas and Ferb Wiki

With my stimulated brain, I am dreaming up all sorts of super smart projects.

— Baljeet

When Baljeet becomes concerned that he is losing his mental edge, his friends invent a cerebral stimulatory hat, or "Brain booster," to help him. But when the hat exceeds expectations and makes Baljeet exponentially smarter, he suddenly views everyone else as beneath him and becomes a threat to civilization by taking Earth's atmosphere and bringing it to the moon. Meanwhile, Dr. Doofenshmirtz plans to use his "Key-Find-Inator" to collect all the keys in Danville in hopes that it will lead to the Key to the City.

Episode Summary

Candace notices that the kids are up to something dangerous, even though it's just playing cards. Baljeet comes in, apologizing that he's late. Buford brings up the question of who invented playing cards. Baljeet claims that ancient Babylonians created playing cards, but Ferb corrects him by telling everyone that the Babylonian Society had been defunct for 1000 years before playing cards were introduced in India. Baljeet then realizes in horror that he was wrong, and concludes that due to the 3 months of Summer Vacation, he is losing his edge. After Baljeet walks away, Phineas says he knows what they're going to do.

At the antique shop, Lawrence is showing a customer around, and shows her a wardrobe that Perry is sitting near. After they walk away, Perry dons his fedora and walks into the wardrobe and into his lair, encountering coats, trees, and snow on his way. Major Monogram then explains the trees were left over from Christmas and that the air conditioning was on the fritz. He then informs Perry that keys across the Tri-State Area are disappearing causing chaos.

In the backyard, Baljeet comes back with two CAT Scans of his brain, one before Summer and one during Summer. Isabella points out that they look the same. Baljeet knows this, but says he is slipping, evidenced by the fact he took three minutes to remember how to give himself a CAT Scan. Phineas then shows Baljeet what they made while he was gone; a helmet that stimulates his brain. The helmet visibly works, as Baljeet performs complex equations to solve how many sub-atomic particles are on a dandelion. Meanwhile, Candace asks Stacy if she still wants to go to the pool.

Perry then appears at Doofenshmirtz Evil Inc., where Doofenshmirtz traps him in a water soluble capsule. He then reveals his plan; to steal all of the keys in the city with his Key-Find-inator, in hopes of finding the Key to the City, believing it will allow him to go anywhere in the city.

Back at Phineas and Ferb's house, Baljeet is still testing the helmet. He reveals his new intelligence has given him a lot of ideas, with his favorite being taking the Earth's atmosphere and placing it on the moon, so that everyone would have a better view out of a telescope. His friends try to talk him out of it, but he continues anyway. Phineas realizes that the brain booster was not such a good idea after all. Buford tries to shut off the helmet's power source, but Baljeet placed a force field around it so no one would shut it off.

Fooling Baljeet with cardboard effigies, Phineas, Ferb, Buford and Isabella make their way under the backyard to get to the atmospheric device. Using jet-packs, they distract Baljeet by flying around the device. Thinking he has stopped them with his tractor beam, Baljeet commences the atmospheric transfer process. Candace walks out, notices the device, and calls Mom, who is stuck at the post office because she can't find her keys.

As the weather grows erratic, the Key to the City ceremony is starting. Just as Roger hands the key to its recipient, the Key-Find-inator zaps it and brings it to him. Due to the rain, Perry is able to escape from the capsule and attack Doofenshmirtz.

Baljeet continues the transfer, as Phineas warns him to surrender. As he realizes that he was fooled by life-sized mannequins, Buford comes and yanks the brain booster off of Baljeet's head, and he returns to normal. Phineas explains that Baljeet was chasing the mannequins while they dug up through the device. Phineas asks if he remembers the mannequins they built earlier. Baljeet says he doesn't. Ferb says "It pays to be on time", prompting Baljeet to get an alarm clock. Realizing his mistake, Baljeet explains that he can't stop the transfer, as he does not remember the controls. Isabella asks if he included a fail-safe. He remembers he did, but he can't find the keys to shut it off.

The Key to the City arrives at Doofenshmirtz's -inator. While he was analyzing how it is more of a decoration, Perry reverses the affect of the -inator, sending all of the keys back where they were and causing it to self-destruct. Despite the -inator being destroyed, Doofenshmirtz doesn't care, since he still got the Key to the City. As Perry leaves, Doofenshmirtz rants more about the key, then is zapped by lightning. As Linda continues looking for her key, it lands in her hand.

As Baljeet is running around frantically trying to find the key before the transfer is complete, it lands on the key hook. One second before the transfer is complete, Baljeet turns the key and stops the process, saving the Earth.

Isabella comments that they should do something about the helmet. Buford interjects; using the helmet, he created the world's largest wedgie machine. And as Candace was about to bring Mom into the backyard, the wedgie machine pulls the atmospheric device into space along with the helmet. Candace complains that the device was there just a second ago, with Linda saying that "It pays to be on time". She asks if anyone wants pie, and all of the kids run in. As Perry walks in, an annoyed and sad Candace says she's "Going to get an alarm clock".


Read the transcript of Cranius Maximus.


End Credits

Second verse of Big Brain.


Click here to view more images from "Cranius Maximus".
View the image gallery for "Cranius Maximus".

Running Gags

The "Too Young" Line

Buford: I think brain boy had enough stimulation for one day. Ow! Hey, that hurts.
Baljeet: Yes, yes, it does.
Isabella: We should do something about that helmet, huh.
Buford: No. No you should not; I used my vastly superior intellect to build the world's largest wedgie machine.

Ferb's Line

Ferb: Actually the Babylonians had been defunct as a distinct culture for millennium prior to the introduction of playing cards in India.
Ferb: It pays to show up on time.

What'cha doin'?


Oh, there you are, Perry

Phineas: Oh, there you are, Perry.

(Perry chatters)

Candace: I'm going to get an alarm clock.

Perry's entrance to his lair

Through a wardrobe in the Antique Shop with everything frozen similar to The Chronicles of Narnia.

I know what we're gonna do today!/Hey, where's Perry?

Phineas: Gang, I know what we're gonna do today!

Buford: And Perry?

Phineas: Who knows?

Memorable Quotes

Baljeet: Clever, but not clever enough.
Isabella: I was so looking forward to junior high.
Buford: No you should not, I created the world's largest wedgie machine.

Baljeet: Uh, you tried to eliminate the atmosphere, one time.

Buford: Ha, ha, ha, ha, ha!

Background Information

  • It is revealed that Isabella could be no older than 10–13 years old, due to her saying, "I was so looking forward to junior high".
  • Technically, Candace would've busted Buford and Baljeet because Phineas and Ferb didn't build the atmospheric transfer device.

Production Information

International Premieres

  • June 22, 2012 (Family Channel)
  • July 19, 2012 (Disney XD Germany)
  • July 21, 2012 (Unitel Bolivia)
  • August 10, 2012 (Disney Channel Latin America and Brazil)
  • November 4, 2012 (Disney XD Spain)
  • December 30, 2012 (Disney XD Latin America)
  • January 7, 2013 (Disney Channel Portugal)
  • January 17, 2013 (Disney XD Poland)
  • March 2, 2013 (Disney Channel Asia)


  • Playing cards actually originated in China, not India, so Ferb and Baljeet were both wrong.
  • When Doofenshmirtz catches Perry, his shirt starts out white, but when he is putting his pants on, it turns black.
  • Baljeet's pocket disappeared and reappeared throughout the episode.
  • In the scene where Baljeet sees the decoy models of the gang, it's shown Ferb before Isabella but when the camera jumps to the backyard it's the opposite, and their gestures are different.
    • Also, the tree is not seen. At the same time, the tape recorder is behind the decoys, but before that shot it was nowhere to be seen.
  • When Baljeet is trying to stop Phineas and his friends a lever is out of place.
  • Candace complains that the tower was here just a second ago, but the time between the wedgie machine pulls the tower into space and she says that is actually nine seconds in real time. (though she could've been exaggerating)
  • When the song begins, at one point Isabella's right bangs are the same color as the sky.
  • In the last shot, Candace's eyes flicker from black to blue and vice versa.



  • Circus Maximus - The episode title is an allusion of Circus Maximus, an ancient Roman chariot racing stadium and mass entertainment venue.
  • The Lion, the Witch, and the Wardrobe - Perry's lair entrance is the same as when Lucy enters the wardrobe and into Narnia. Also, Lawrence jokingly says that the closet at his antique shop had a secret land in it with mystical creatures, much like Narnia is.
  • X-Men - Phineas and Ferb's helmet resembles Professor Xavier's helmet in Cerebro.
  • Archie's Weird Mysteries - The whole idea of a character who is slightly dumb being turned a real genius, and being good at it, due to a malfuntion cap is very similar to the plot of the Archie's Weird Mysteries episode "Brain of Terror".



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