Jack Black

R.L. Stine / Slappy (voice) / Invisible Boy (voice)

Dylan Minnette

Zach Cooper

Odeya Rush

Hannah Fairchild

Ryan Lee

Champ

Amy Ryan

Gale Cooper

Jillian Bell

Lorraine Conyers

Halston Sage

Taylor

Steven Krueger

Davidson

Keith Arthur Bolden

Principal Garrison

Amanda Lund

Officer Brooks

Timothy Simons

Officer Stevens

Ken Marino

Coach Carr