Which Came First?
Which Came First Title Card
Series The Grim Adventures of Billy & Mandy
Season 3
Production code 317
Writer Matt Sullivan
Vincent Waller
Broadcast information
Cartoon Network US Premiere July 30, 2004
Paired with Substitute Teacher
Chronological information
Substitute Teacher
Super Zero

Which Came First? is the 17th and final episode from season 3 of The Grim Adventures of Billy & Mandy.


While going to a school excursion, Billy and Mandy's schoolbus breaks down in the middle of a desert. They, later, eventually learn that mutant chickens created in an underground lab during the Cold War lurk around.


  • Story by: Matt Sullivan, Vincent Waller
  • Storyboard by: Vincent Waller
  • Art direction: Rae McCarson
  • Directed by: Brian Sheesley


Which Came First?/Transcript


  • The episode is a parody of Jurassic Park.
  • The storyboard artist of this episode is Vincent Waller, the creative director of Nickelodeon's SpongeBob SquarePants
  • Fourth Wall Break: Mandy stating that the "Writer's Conscience" will help to explain the mutant chickens, right before a professor conveniently shows up to fill them in on what's been going on.


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