|Which Came First?|
|Series||The Grim Adventures of Billy & Mandy|
|Writer|| Matt Sullivan|
|Cartoon Network US Premiere||July 30, 2004|
|Paired with||Substitute Teacher|
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
- 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.
|The image gallery for Which Came First? may be viewed here.|