Characters played by Judy Greer
Beep
Characters played by Erin Fitzgerald
Bo
Eardrum
Roxy
Stapes
Characters played by Fred Tatasciore
Bang
Band
Incus
Ned the Neutron
Characters played by Jeff Gill
Bing
Characters played by Gregg Spiridellis
Boop
Francis
Characters played by Evan Spiridellis
Hap
Stinky Bart
Characters played by Jim Meskimen
Bob Fossil
Brock O. Lee
Droppy
Horn Head
Pierre the Fly
The Mayor
Tony Mousetana
Wise Old Owl
Characters played by Nate Theis
Hub and Bub
Additional voices
Hub & Bub
Characters played by Randy Crenshaw
Cochlea
Malleus
Pat
Rodney Potato
The Artist
Characters played by Eric Bauza
Jake the Cupcake
Mr. Recorder
Characters played by John DiMaggio
Mr. Sun
Mr. Whale
Characters played by Eddie West
Sheriff Brushy
Characters played by Riki Lindhome
Special Guest Appearance
Characters played by Kevin Smith
Special Guest Appearance
Characters played by Chris Parnell
Special guest appearance
Characters played by Jay Leno
Special Guest Appearance
Characters played by David Boat
Molephius
Characters played by Whoopi Goldberg
The Tooth Fairy
Characters played by Kate Micucci
Special Guest Appearance
Characters played by Tim Meadows
Special guest appearance
Characters played by Katelyn Nagoray
Self - Interviewee
Characters played by Spencer Park
Self - Interviewee
Characters played by 'Weird Al' Yankovic
Special Guest Appearance
Characters played by Daxter Cuthbertson
Self - Interviewee
Characters played by London Sizemore
Self - Interviewee
Characters played by Eva Stikeleather
Self - Interviewee
Characters played by Kiran Jyothi
Self - Interviewee
Characters played by Edward Norton
Gary the Electronics Salesman
Characters played by Kristen Schaal
Special Guest Appearance
Characters played by Christina Applegate
The Baker
Characters played by Ali Wong
The Brain
Characters played by David Cross
Special guest appearance
Characters played by David Koechner
Captain
Characters played by Snoop Dogg
Operating System
Characters played by John Legend
The King of Music
Characters played by Dave Goelz
Mr. Caterpillar
Characters played by Taylor Meskimen
[no data]
Characters played by Ill Camille
Bobby Boombox
Characters played by Malachi Elijah Anderson
Self
Characters played by Edwin E.J. King Jr.
Self - interviewee
Characters played by Erica Dawson
Ms. Spider
Characters played by Alyssa Milano
The Chocolatier
Characters played by Maria Bamford
Dr. Pat the Mad Scientist
Characters played by Tony Hale
Chuck
Special Guest
Characters played by Mia Lynn Bangunan
Mia
Characters played by Lennon Grace
Self - Interviewee
Characters played by Lily Judge
[no data]
Characters played by Kristen Carter
Earth
Characters played by Kailen Jude
Self (Guest Star)