The Secret Decoder Ring
The Secret Decoder Ring Title Card
Series The Grim Adventures of Billy & Mandy
Season 4
Production code 422
Writer Zena Wyss

Mike Diederich

Broadcast information
Cartoon Network US Premiere April 15, 2005
Paired with Happy Huggy Stuffy Bears
Chronological information
Happy Huggy Stuffy Bears
Wild Parts
The Secret Decoder Ring is the 22nd episode from season 4 of The Grim Adventures of Billy & Mandy.


Billy tries to use a decorder ring that he finds in a cereal box in order to discover the secret of the universe. Grim tries to warn Billy and Mandy off of seeking out 'secret of the universe', suspecting the hand of a figure from his past. The weird thing is, Billy and Mandy are not the only ones trying to discover the 'secret of the universe'...


  • Story by: Zena Wyss, Mike Diederich
  • Storyboard by: Mike Diederich
  • Art direction: Rae McCarson
  • Directed by: Robert Alvarez, Shaun Cashman, Randy Myers


  • A hidden message can be seen within the frames in the episode. It's possibly an editing error.

    The hidden message


Grim, Billy and Mandy at cereal
The image gallery for The Secret Decoder Ring may be viewed here.