Queen Agatha appears in The Sesame Street Treasury Volume 1, in "An A Story." Initially shrouded from view beneath a mass of golden locks and flowing robe, Queen Agatha rules over a nameless kingdom, and calls for her knights, including Sir Bird, to bring her something beginning with the letter A; the winner will dance with her majesty at the royal party.
Sir Bird presents the queen with an alligator, only for Queen Agatha to reveal herself as an alligator, who prefers Sir Bird's friend, "a pretty handsome guy, you know that?" Still, she graciously rewards Big Bird with a lifetime suppply of birdseed and a position as ambassador to Antarctica.