Tim Allen

Jack Sheppard

Courteney Cox

Marsha Holloway

Chevy Chase

Dr. Grant

Spencer Breslin

Tucker Willams / Mega-Boy

Kevin Zegers

Connor Shepard / Concussion

Kate Mara

Summer Jones / Wonder

Michael Cassidy

Dylan West / Houdini

Ryan Whitney

Cindy Collins / Princess

Rip Torn

Larraby

Cornelia Guest

Cindy's Mom

Ashton Moio

Halloween Bully

Thomas F. Wilson

Dylan's Teacher

Ridge Canipe

Mean Bully

Danny McCarthy

Meaner Bully

David L. Lander

Wendy's Employee

Lauren Sánchez Bezos

Reporter

Willie Garson

Dick

Zoe Doyle

Researcher

Kendra Rose Montagna

Cheerleader

Aaron Abrams

Corporal Lipscombe (uncredited)

Nick Baga

Fat Swimmer (uncredited)

Alexis Bledel

Ace (uncredited)

Darryl Dinn

Lab Researcher (uncredited)