|| Aww! This was when Rockhopper discovered Yarr. What an amazing day!
— Rockhopper's Joy
Rockhopper's Joy is the penguin manifestation of the emotion of joy within Rockhopper. Players could obtain her costume at the Inside Out Party. She is the main emotion at the party and in the film.
During the party, Rockhopper's five core memories go missing, with one corresponding to each emotion. Rockhopper's core memory for Joy was finding Yarr, his Red Puffle.
Rockhopper's Joy on a party homepage screen
After finding the joy memory orb
After returning the joy memory orb
Inside Out Party 2015 Evolution of Joy - Disney Club Penguin
Disney Pixar Inside Out Party Joy and Fear