Brain Switch / Koikawa Harumachi
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Season 3, Episode 5
Vital statistics
Air date 2016
Written by Unknown
Directed by Unknown
Episode guide
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Climate Control / Ziryab Super Sherman / Ada Lovelace
Brain Switch / Koikawa Harumachi is the 31st episode of The Mr. Peabody & Sherman Show.


Sherman is sick of being a kid and wants to grow up right away, so he and Mr. Peabody switch brains to see what it's like to be in each others shoes; Koikawa Harumachi is drawing the world's first Japanese manga and literally pulls our intrepid duo into his epic fantasy.


  • Harumachi draws Mr. Peabody and Sherman into an Anime-manga style when he pulls them into his manga. Their designs look similar to that of Doraemon and Nobita from the Doraemon series.
  • Mr. Peabody draws himself terribly, since he is a science person.
  • Sherman draws Mr. Peabody in his design from The Rocky & Bullwinkle Show, which Peabody doesn't approve of.
  • Penny Peterson was breifly mentioned by Mr. Peabody when asking Sherman how she is to which Sherman replies she's doing good.
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"Ugh, I'm old!"