Magic School Bus In The City", the bus, after becoming a bear, wanders off from the class into the city looking for food. Its abilities are due to unspecified, magical additions, the origins of which are never fully explained, although it would appear that the new components are subtle enough to avoid attracting much attention from outsiders as the bus is often seen undergoing inspection without anyone commenting on its additions. The Bus is capable of transforming into multiple objects, ranging from a speck of pollen to a time machine to a small planet, though its trademark form is that of a rocket. Some of the bus's technologies also have specific names. For example, the device that allows the bus to shapeshift is called the "Mesmerglober", and the device that allows it to change size is called the "Shrinkerscope", (a portable version is called the Porta-shrinker); the Dew-Dinger is the device used to indicate whether the Shrinkerscope is wet, in which case it won't work. Another device is called the "Apidemonflemonjab", which is what caused the bus to malfunction in "Gets Ready, Set, Dough." Its exact function is never specified. In some transformations, the bus itself comes in different colors, such as it turning green when it turned into an alligator, though it typically retains its major features such as its passenger compartment and windows, square headlight fixtures, and chrome grille and hood spine. Some episodes have featured the class having to deal with problems in the Bus itself, such as a field trip to a bakery being jeopardized when the bus shrank unexpectedly. Relatives Frizzle family Dottie Frizzle is Valerie's niece who appears in a 1997 book. Murph is Valerie's southern-accented cousin. Her full name is Katrina Eloise Murphy and she is specifically a first cousin who owns and operates Murph's Recycling Plant. She teaches the class the value of recycling in the 1996 episode "Holiday Special". She often warns everyone to be careful when using the word "junk." Voiced by Dolly Parton. Janet Perlstein Voiced by Renessa Blitz (original series), Annelise Forbes (Rides Again) Janet Perlstein is Arnold's know-it-all, conceited cousin. She is cruel to others and actively seeks to make their lives worse, only ever acting in her own interests. She is very unpopular among the class, though she did manage to manipulate them into siding with her (and turning on Phoebe) when it came to naming