This special was a short that was played right at the start of The Powerpuff Girls Movie on July 3, 2002.
Dee Dee: Dexter, is that you? What happened?
Dexter: I scratched.
DeeDee: Well, a long time ago a group of evil contaminated chickens escaped from jail and started to break into children's houses, where they pecked away, leaving huge, itchy pimples. And if you scratch them, you'll turn into an evil contaminated chicken.
Dexter: Are you crazy, woman?! (starts scratching)
DeeDee: (uttering) Bock! Bock!
Dexter: (screams) Ahhh! I don't want to be an evil contaminated chicken.
DeeDee: Then don't scratch! (leaves room)
This is the last time Allison Moore voices Dee Dee.
According to Dee Dee, if Dexter scratched he would be turned into a chicken.
Near the end when Dexter is laughing, old sound clips of Christine Cavanaugh as Dexter laughing were used.
This episode aired in the UK before anywhere in the world on TV, not including with movie airings.
This short will air in the middle of the Season 4 episode "The Lab of Tomorrow / Poetic Justice".
The animation is distinctly different in this short film
This is the only Dexter episode that can be seen on DVD, which will be in with the PowerPuff Girls movie DVD.
This episode originally aired in theaters along with the Powerpuff Girls movie. (So it's eligible for the "Animated Short Film" category on the Oscars next year) It is unknown so far if it will be inserted as part of the TV show.
This was based on a story in a Dexter's Lab comic book