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|1 = The Lean Mean Brain Machine |2 = TLMBM |3 = 2 |4 = Unaired |5 = Phineas and Ferb Meet RHF |6 = Ferb-eo Game }}

Phineas and Ferb build a brain switching machine to see what it's like in other peoples' shoes, who end up switching brains with Perry the Platypus and RHF and become Perr (Perry in Ferb's body), Ferbeas (Ferb in Phineas's body), Phin-fu (Phineas in RHF's body (known as Rufu in Japan)), and Ruffy the Platypus (RHF in Perry's body).


Phineas, Ferb, and RHF build a brain switching machine. They explain to Mrs. Flynn that it's to see what it's like in Perry's shoes. Unfortunately, the four switch brains instead of just one with Perry, and their machine breaks. RHF in Perry's body decides that they be temporarily known as Perr (Perry in Ferb's body), Ferbeas (Ferb in Phineas's body), Phin-fu (Phineas in RHF (known as Rufu in Japan)'s body), Fatrica (Patrica in Florence body) and Plorence (Florence in Patrica's body),and Ruffy the Platypus (RHF in Perry's body), . They try to get back to normal, but they just realized their machine broke. Perr learns English, and trick Phin-fu into signing an alleged blank certificate of stealing Doofenshmirtz's latest invention, but he realizes that Perr already signed it. The two argue, but Ruffy the Platypus breaks up the fight. Hopefully, they return to normal.

Memorable Quotes

The "Too Young" Line

Not asked in this episode.

Ferb's Line

Ferb mentions Russian Reversal.

RHF: to Mrs. Flynn Doesn't Candace normally call you?

Ferb: Maybe we're in Soviet Russia.

Florence's ocansional line's

Florence: If we we're we would be ice skating around the world in 80 days.

Whatcha Doin'?

Asked by Isabella to Phineas, not knowing that he was Ferb in Phineas's body.