Marcia the Martian is Marvin the Martian's apprentice and niece. She only appeared in the "Duck Dodgers Jr." segment of the episode "The Return to the Acme Acres Zone", where she went up against Duck Dodgers and Plucky Duck. At the end, she and Plucky decided to go off and play, while Marvin and Dodgers duke it out.
Marcia enjoys playing with building blocks, and is a very fast speaker. She appears in only one episode and befriends Plucky Duck, despite her uncle being his mentor’s archnemesis. Marcia wears a pink jumper and trousers with a purple skirt and a cone party hat that has a pink bow. Her sneakers resemble those worn by her uncle.
- Mike Kazaleh recollects that Marcia was intended to be Marvin's daughter.