The Yellow Queen

Queen Yellow appeared in the Sesame Street Live show Sleeping Birdie. She is the queen of Planet Crayon, the home of Big Bird's friend Tee Hee. She once thought she was "the yellowest of them all" until she visited Sesame Street and discovered Big Bird. She then devised a plan to put purple polka dots all over our feathered friend, but her plan backfired and she ended up with polka dots on herself. However, The Amazing Mumford quickly changed her back to her yellow self doing one of his magic tricks. The Queen learned a lesson about diversity and acceptance of one another.

A similar plot was used in another Sesame Street Live show, Elmo's Coloring Book. Blanche the Polar Bear is sort of the antagonist, and instead of adding extra colors, she stills them. This would result in a bunch of chaos amongst the Sesame Street gang.