You'd think a major advantage of robots is you can mass-produce them. They're just metal-and-circuit bodies. But science fiction is full of one-of-a-kind bots. Here are all the bots for whom they broke the mold.

We've divided our list of weirdly unique robots into four categories: experimental prototypes, bizarre one-offs created for a specific purpose, the creations of mad inventors tinkering in their labs, and robots building other robots from scrap. There's probably some overlap between these categories - mad scientists often create a one-off robot, thinking it's a prototype for a whole line of similar bots - but we'll try and keep them straight as best we can.

Some quick notes. Two of the most iconic robots on this list actually both have twin brothers, and one of them even had a separate prototype. But since all five of these robots were the product of individual roboticists and never meant as part of a larger production line, we're still including them. Plus, this list would be simply incomplete without them.

There are also quite a few robots on here who got rebuilt when they were destroyed or lost. Technically, that means they're not unique. We're keeping them on the list as long as, broadly speaking, we only saw them sequentially and the intention wasn't to allow for multiple copies to interact. (As with most things, time travel does tend to complicate this.)

Finally, one of the trickier shows to deal with was Futurama, which has a huge variety of robots, any of which could be unique. To keep this list manageable, we zeroed in on the ones that were either explicitly meant to be the only one, or those that no one in their right mind would ever mass-produce (I mean, who would mass-produce gangster robots?). It's not exactly cut and dried, but that's our logic.

An experimental prototype:

Robot: The Human Torch, from Marvel Comics #1
Inventor: Phineas Horton
Year: 1939
Creator/writer: Carl Brugos

Robot: Hymie The Robot, from Get Smart
Inventor: Dr. Ratton
Year: 1965
Creator/writer: Mel Brooks and Buck Henry

Robot: The K-1 Robot, from Doctor Who, "Robot"
Inventor: Professor Kettlewell
Year: 1974
Creator/writer: Terrence Dicks

Robot: KARR and KITT, from Knight Rider
Inventor: Wilton Knight
Year: 1982
Creator/writer: Glen Larson

Robot: Daryl, from D.A.R.Y.L.
Inventor: U.S. government
Year: 1985
Creator/writer: Simon Wincer

Robot: Johnny 5, from Short Circuit
Inventor: U.S. government and Steve Guttenberg
Year: 1986
Creator/writer: S.S. Winston & Brent Maddock

Robot: Marvin The Paranoid Android, from The Hitchhiker's Guide To The Galaxy
Inventor: The Sirius Cybernetics Corp.
Year: 1978
Creator/writer: Douglas Adams

Robot: Data, Lore, and B4, from Star Trek: The Next Generation
Inventor: Noonien Soong
Year: 1987
Creator/writer: Gene Roddenberry

Robot: The Werecar, from Futurama
Inventor: The U.S. Government
Year: 1999
Creator/writer: David X. Cohen and Matt Groening

Robot: David, from A.I.: Artificial Intelligence
Inventor: Cybertronics Corporation
Year: 2001
Creator/writer: Steven Spielberg, Brian Aldiss, Ian Watson

A bizarre one-off created for some whimsical/sick purpose:

Robot: Ro-Man, from Robot Monster
Inventor: Unknown
Year: 1952
Creator/writer: Phil Tucker

Robot: Robot Archie, from Lion #1
Inventor: C.R. Richie
Year: 1952
Creator/writer: E. George Cowan and Ted Kearnon

Robot: Mechani-Kong, from King Kong Escapes
Inventor: Doctor Who (no, not that one.)
Year: 1967
Creator/writer: Ishiro Honda

Robot: Red Tornado, from Justice League Of America #64
Inventor: T.O. Morrow
Year: 1968
Creator/writer: Gardner Fox and Dick Dillin

Robot: MechaGodzilla, from Godzilla vs. MechaGodzilla
Inventor: The Simians
Year: 1974
Creator/writer: Jun Fukuda

Robot: K-9 from Doctor Who, "The Invisible Enemy" (later duplicated, however.)
Inventor: Professor Marius, sort of
Year: 1977
Creator/writer: Bob Baker and Dave Martin

Robot: Tom Servo, Crow T. Robot, Gypsy and Cambot, from Mystery Science Theater 3000
Inventor: Joel Hodgson
Year: 1988
Creator/writer: Joel Hodgson

Robot: Tomorrow Woman, from Justice League #15
Inventor: T.O. Morrow and Professor Ivo
Year: 1997
Creator/writer: Grant Morrison and Howard Porter

Robot: Santabot, from Futurama
Inventor: Mom's Friendly Robot Company
Year: 1999
Creator/writer: David X. Cohen and Matt Groening

Robot: Reverend Preacherbot, from Futurama
Inventor: Unknown
Year: 1999
Creator/writer: David X. Cohen and Matt Groening

Robot: Kwaanzabot, from Futurama
Inventor: Unknown
Year: 1999
Creator/writer: David X. Cohen and Matt Groening

Robot: Hedonismbot and his servent Djambi, from Futurama
Inventor: Our tax dollars
Year: 1999
Creator/writer: David X. Cohen and Matt Groening

Robot: The Robot Devil, from Futurama
Inventor: Unknown
Year: 1999
Creator/writer: David X. Cohen and Matt Groening

Robot: The Robot Mafia of the Donbot, Joey Mousepad, and Clamps, from Futurama
Inventor: Unknown
Year: 1999
Creator/writer: David X. Cohen and Matt Groening

Robot: Tinny Tim, from Futurama
Inventor: Unknown
Year: 1999
Creator/writer: David X. Cohen and Matt Groening

Robot: Red Volcano, from DC Universe #0
Inventor: Professor Ivo
Year: 2008
Creator/writer: Grant Morrison and Geoff Johns

A mad inventor throwing shit together:

Robot: Talos, from the Argonautica
Inventor: Hephaestus
Year: 3rd century B.C.
Creator/writer: Apollonius Of Rhodes

Robot: Steam Man, from Steam Man Of The Prairies
Inventor: Jonny Brainerd
Year: 1868
Creator/writer: Edward S. Ellis

Robot: Hadaly, from The Future Eve
Inventor: Thomas Edison
Year: 1886
Creator/writer: Auguste Villiers de l'Isle-Adam

Robot: Tik-Tok, from Ozma Of Oz
Inventor: Smith And Tinker
Year: 1907
Creator/writer: Frank L. Baum

Robot: Maria, from Metropolis
Inventor: C.A. Rotwang
Year: 1927
Creator/writer: Fritz Lang

Robot: Adam Link, from I Robot
Inventor: Dr. Link
Year: 1939
Creator/writer: Earl and Otto Binder

Robot: Stephen Byerly, from "Evidence" in I, Robot
Inventor: The original Stephen Byerly
Year: 1946
Creator/writer: Isaac Asimov

Robot: R. Daneel Olivaw and R. Jander Panell, from The Caves Of Steel
Inventor: Han Fastolfe
Year: 1954
Creator/writer: Isaac Asimov

Robot: Robby The Robot, from Forbidden Planet
Inventor: Dr. Edward Morbius
Year: 1956
Creator/writer: Fred M. Wilcox

Robot: Amazo, from The Brave And The Bold #30
Inventor: Professor Ivo
Year: 1960
Creator/writer: Gardner Fox

Robot: Jana from Twilight Zone, "The Lateness Of The Hour"
Inventor: Dr. Loren
Year: 1960
Creator/writer: Rod Serling

Robot: C-3PO, from Star Wars (This one is tricky because we do see other models of him, but his origins clearly make him unique.)
Inventor: Anakin Skywalker (well, he's more accurately his builder, but still...)
Year: 1977
Creator/writer: George Lucas

Robot: Robert The Robot, from Fireball XL5
Inventor: Professor Matt Matic
Year: 1962
Creator/writer: Gerry Anderson

Robot: Astro Boy, from Astro Boy
Inventor: Doctor Tenma
Year: 1963
Creator/writer: Osamu Tezuka

Robot: The Metal Men, from Showcase #37
Inventor: Dr. Will Magnus
Year: 1962
Creator/writer: Robert Kanigher, Ross Andru and Mike Esposito

Robot: Awesome Android, from Fantastic Four #15
Inventor: The Mad Thinker
Year: 1963
Creator/writer: Stan Lee and Jack Kirby

Robot: Beautie (although she admittedly is based on a popular line of dolls) from Astro City
Inventor: Elaine Girbachs
Year: 1995
Creator/writer: Kurt Busiek, Brent Anderson, and Alex Ross

Robot: Torg, from Santa Claus Conquers The Martians
Inventor: Martians
Year: 1964
Creator/writer: Nicholas Webster

Robot: Braman, from Thunderbirds
Inventor: Brains
Year: 1964
Creator/writer: Gerry Anderson

Robot: Ultron, from Avengers #54
Inventor: Henry Pym
Year: 1968
Creator/writer: Roy Thomas and John Buscema

Robot: R. Giskard Reventlov, from The Robots Of Dawn
Inventor: Han Fastolfe
Year: 1983
Creator/writer: Isaac Asimov

Robot: Bentley the Robot, from Fireman Sam
Inventor: Sam Jones
Year: 1985
Creator/writer: Dave Gingell and Dave Jones

Robot: Pneumon, from Tom Strong #1
Inventor: Sinclair Strong
Year: 1999
Creator/writer: Alan Moore and Chris Sprouse

Robot: Steelgauntlet, from Top 10: The 49ers
Inventor: Frank Chambers
Year: 2008
Creator/writer: Alan Moore and Gene Ha

Robot: Zoe Graystone, aka Zoe-R, from Caprica
Inventor: Daniel Graystone and Zoe Graystone, with some outside help
Year: 2009
Creator/writer: Ron Moore, David Eick, Remi Aubuchon, and Jane Espenson

Robots building other robots, one at a time

Robot: The Vision, from Avengers #57
Inventor: Ultron
Year: 1968
Creator/writer: Roy Thomas and John Buscema

Robot: Jocasta, from Avengers #162
Inventor: Ultron
Year: 1977
Creator/writer: Jim Shooter and George Perez

Robot: Lal, from Star Trek: The Next Generation, "Offspring"
Inventor: Data
Year: 1990
Creator/writer: Gene Roddenberry

Robot: All of the boppers in Rudy Rucker's 'Ware series.
Inventor: Originally, Cobb Anderson helps to create intelligent robots, and gives them free will. But eventually, the bots start building other bots, each with its own quirky makeup and zany personality.
Year: 1982
Creator/writer: Rudy Rucker

Robot: Norby, from Norby The Mixed-Up Robot
Inventor: Mentor First
Year: 1983
Creator/writer: Janet Asimov

Robot: Val and Aqua, from Heartbeeps
Inventor: Unknown
Year: 1981
Creator/writer: Allen Arkush

Robot: Alkhema, from Avengers West Coast #90
Inventor: Ultron
Year: 1993
Creator/writer: Roy & Dann Thomas, David Ross & Tim Dzon

Robot: All the robots in Robots
Inventor: Unknown
Year: 2005
Creator/writer: Chris Wedge and Carl Saldanha

Robot: All the Transformers in Transformers (but especially Soundwave)
Inventor: The Quintessons
Year: 1984
Creator/writer: The Takara and Hasbro toy companies

Additional writing/reporting by Alasdair Wilkins. WeRobot T-shirt image, up top, via BotJunkie.

Send an email to Charlie Jane Anders, the author of this post, at charliejane@io9.com.