Guest stars
Scott Adsit as Adam the Moon-Baby (in "Pilot")
Carlos Alazraqui as Count Dracula (in "Triangle")
Diedrich Bader as Martin Popple (in "Purchase"), Tony the Vampire (in "Purchase"), Party Leader Tony (in "David"), Soldier (in "David")
Iris Bahr as Commandante Dulac (in "Purchase")
Troy Baker
Maria Bamford as Soul Ganderer (in "Triangle")
Eric Bauza as John Wilkes Booth Clone (in "Ghosts")
Alex Brightman as Peterson (in "Hollow")
Mikey Day as Logan Parks ("Ghosts")
Grey DeLisle as Francis O'Doyle's Mother (in "Ex")
Chris Diamantopoulos as Bob (in "Triangle"), Demon Inmate (in "Triangle")
Ryan Elder as Chet Simmons (in "David")
Nat Faxon as Michael in Accounting (in "Purchase", "David")
Janeane Garofalo as Chief Usher Cherri (in "David")
Jon Glaser as Chef Matteo (in "David")
Dan Harmon as Stanley Kubrick (in "Pilot")
David Herman as Abraham Lincoln's ghost (in "Ghosts")
John Michael Higgins as Ken Jeffries (in "Triangle")
Gillian Jacobs as Elsie (in "Purchase")
Echo Kellum as Werewolf Syndicate Leader (in "Ex"), Head of Homeland Security (in "Ex"), West Wing World Robots (in "Ex")
Kerri Kenney-Silver as Sandra in Catering (in "David")
Thomas Lennon as Koochoo (in "Hollow")
Jane Lynch as Party Leader Susan (in "David")
Ken Marino as Captain Marks (in "Hollow")
Piotr Michael
Jaime Moyer
Nolan North
Adam Pally as Lead Triangle Guard (in "Triangle"), Coast Guard Member (in "Triangle")
Maulik Pancholy as Reporter Frank (in "Hollow")
Rafael Petardi as French Soldier (in "Purchase")
Danny Pudi as Amil Bhattam (in "Purchase")
Nick Reczynski as Robot President (in "Ex"), Wine-Red Sweater Guy (in "Ex"), Court Security Guard (in "Purchase"), Kyle (in "David"), Driver (in "David"), Trent McGaffin's Father (in "David")
Sam Richardson as Two-Toes (in "Hollow"), Booger (in "Ghosts")
Rino Romano
Stephen Root as Toomoo (in "Hollow")
Kristen Schaal as Amelia Earhart (in "Triangle")
Rob Schrab as Spider Inmate (in "Triangle")
Kelsey Scott as Governor Beverly "Bev" Mills (in "Ex")
James Siciliano
Roman Siciliano
Timothy Simons as Dr. Keel (in "Hollow")
Andy St. Clair as Archian Pilot (in "Hollow"), Nickel King (in "Hollow"), White House Operator (in "Ghosts")
Colette St. Clair
Chris Sullivan as Metaldetectoid (in "Triangle")
Cree Summer as David the Water Witch (in "David"), Curtis' Imaginary Son (in "David")
Fred Tatasciore as Swamptopus (in "Triangle")
Danielle Uhlarik as Stuckey (in "Pilot"), A.I. Bomb (in "Pilot"), White House Reporter (in "Pilot"), Mushroom Queen (in "Hollow")
Imari Williams as Daniel Robitaille / Candyman (in "Ex")
Debra Wilson as Curtis' Mom (in "David"), Lisa (in "David")
Billy Zane as Salem Montgomery (in "Purchase")
