Ming Tsai of Simply Ming appears in the episode "What's Cooking?" as a judge for a kids' cooking contest at Arthur's school. Neil Gaiman appears in the episode "Falafelosophy", where he offers Sue Ellen advice about the graphic novel she is writing after meeting her at a falafel stand. Rodney Gilfry appears in the episode "Lights, Camera... Opera!" with a role in the Carmen opera that Muffy and Ed Crosswire attend. R. L. Stine appears as Buster's uncle Bob Baxter. Taj Mahal appears in the episode "Big Horns George" with Koko Taylor. Yo-Yo Ma appears in the episode "My Music Rules" with Joshua Redman. After D.W. attends his concert, she invites him to perform at the local library. The episode ends with him and Joshua Redman discussing the merits of different types of music. Alex Trebek appears as a fictional version of himself, Alex Lebek, as the host of the game show "Riddle Quest", on which Arthur is a contestant. Imaginary friends Maxine is D.W.'s imaginary friend. She appears as an elephant with an exotic purple hair style. Nadine Flumberghast (voiced by Hayley Reynolds) is D.W.'s imaginary friend. She appears as a brownish-yellow squirrel with small buck teeth and long, platinum-white blonde hair styled exotically in three pigtails atop her head. She represents D.W.'s conscience and usually appears when D.W. feels guilty, scared, or angry. Both D.W. and Nadine are aware that Nadine is imaginary. However, Kate, Mei-Lin, animals, and other characters' imaginary friends can see and communicate with her. In one episode, she is shown with D.W. when she is much older; in another, D.W. is shown to need Nadine less than before. She can create and destroy imaginary items with magic. Her last name was revealed to be "Flumberghast" in the episode, "Read and Flumberghast". Rapty is Bud's imaginary friend. He is a big green dinosaur. Though he is actually a toy, Bud imagines him as real. In "D.W. & Bud's Higher Purpose", it is shown that he can communicate and talk to Nadine. Trini is Vicita's imaginary friend. She is a very intelligent and truthful fairy, and, in one episode where the imaginary friends team up, she is the unelected leader of the group. Uncle Wormy is the Tibble Twins' imaginary friend. He is a giant slimy worm with one, red eye, and wears a belt with the initials "U.W." on it, standing for his own name.