Greg Eagles

Grim / Sperg (voice)

Richard Steven Horvitz

Billy / Billy's Dad (voice)

Grey DeLisle

Mandy (voice)

Vanessa Marshall

Irwin (voice)

Kari Wahlgren

Velma Green the Spider Queen (voice)

Maxwell Atoms

Jeff the Spider (voice)

Dee Bradley Baker

Chocolate Cow (voice)

Jennifer Hale

Gladysaur (voice)

Chris Cox

Principal Goodvibes (voice)

Jane Carr

Pud'n (voice)

Henry Gibson

Lord Pain (voice)

Phil LaMarr

Mr. Spleen (voice)