Special Guest Stars Lily Tomlin voices Professor Fizzle Nathan Fillion voices Axle ValveStuck Martin Short voices Tony Tennelli Catherine O'Hara voices Aunt Tennelli Catherine O'Hara voices Teresina Tennelli Jay Baruchel voices Dr. Tillage Guest Stars Birva Pandya voices Jyoti Lynsey Pham voices Wanda Gabby Clarke voices Dorothy Ann Kaden Stephen voices Tim Matthew Mintz voices Ralphie Mikaela Blake voices Keesha Miles Koseleci-Vieira voices Arnold Co Starring Ana Sani voices Additional Voices Stuart Stone voices Additional Voices Annelise Forbes voices Additional Voices Lilly Bartlam voices Additional Voices Marcus Craig voices Additional Voices Martin Roach voices Additional Voices Kevin Vidal voices Additional Voices