Will Forte

Character: Shaggy Rogers (voice)

Frank Welker

Character: Scooby-Doo / Pterodactyl (voice)

Mark Wahlberg

Character: Blue Falcon (voice)

Jason Isaacs

Character: Dick Dastardly (voice)

Ken Jeong

Character: Dynomutt, Dog Wonder (voice)

Amanda Seyfried

Character: Daphne Blake (voice)

Gina Rodriguez

Character: Velma Dinkley (voice)

Zac Efron

Character: Fred Jones (voice)

Iain Armitage

Character: Young Shaggy (voice)

Ariana Greenblatt

Character: Young Velma (voice)

Mckenna Grace

Character: Young Daphne (voice)

Pierce Gagnon

Character: Young Fred (voice)

Kiersey Clemons

Character: Dee Dee Skyes (voice)

Tracy Morgan

Character: Captain Caveman (voice)

Simon Cowell

Character: Simon Cowell (voice)

Harry Perry

Character: Harry Perry (voice)

Kevin Heffernan

Character: Bike Cop Gary (voice)

Christina Hendricks

Character: Officer Jaffe (voice)

Henry Winkler

Character: Keith (voice)

John DiMaggio

Character: Restaurant Owner (voice)

Ira Glass

Character: Ira Glass (voice)

Henry Kaufman

Character: Chad / Chet (voice)

Maya Erskine

Character: Judy Takamoto (voice)

Billy West

Character: Muttley (voice)

Don Messick

Character: Muttley (archive sound) (voice)

Fred Tatasciore

Character: Cerberus (voice)

Kennedy Peil

Character: Indira Knight (voice)

John McDaniel

Character: Hal Murphy (voice)

Ryan Folsey

Character: Beach Guy (voice)

Justina Machado

Character: Jamie Rivera (voice)

Pam Coats

Character: Mrs. Rogers (voice)

Tony Cervone

Character: Ghost / Mr. Rigby / Alice (voice)

Alex Kauffman

Character: Officer North (voice)

Vanara Taing

Character: Baby Rotten (voice)

Sarah Lancia

Character: Dispatcher Stevens (voice)

Eric Cowell

Character: Ben (voice)

Maven Morgan

Character: Kari (voice)

Adam Sztykiel

Character: Officer Casey (voice)

Michael Kurinsky

Character: Samuel Colton (voice)