In the TV show "BUTTERFLY AND THE BOG BEAST," the class needs a new mascot for their soccer team. Everyone laughs at Phoebe when she suggests using a butterfly, and Arnold's know-it-all cousin, Janet, suggests the mysterious Bog Beast instead. Ms. Frizzle takes them on a field trip to Butterfly Bog where they discover camouflage and other butterfly tricks of deception — learning just how clear and unwhimpy butterflies can be — while unmasking the mysterious Bog Beast!