Susan Sarandon

as Dr. Helen Wong (voice)

Kari Wahlgren

as Jessica (voice)

Cassie Steele

as Tammy Gueterman (voice)

Nolan North

as Additional Voices (voice)

Dan Harmon

as Phoenixperson (voice)

Maurice LaMarche

as Abradolph Lincler (voice)

Nick Reczynski

as Gromflomite Spokesman / Timothy / Gromflomite Guard #2 (voice)