With a sub-barrel-bottomed budget, this 1958 Mexican horror outing features wicked old Dr. Krupp, a.k.a. "The Bat", the crazed experimenter who caused trouble in this film's two predecessors, The Aztec Mummy and Curse of the Aztec Mummy (both 1957), up to his old tricks. As in the former features, he is again trying to trick the Aztec mummy Popoca into leaving his crypt so the bad doctor can get at the treasure within. This time his scheme entails the invention of the titular tin man (complete with incandescent light-bulb ears), a device he equips with a human brain. A horrific battle ensues when the two monsters collide.
For the Mystery Science Theater 3000 version, please go to the episode recap page.
The Robot vs. the Aztec Mummy provides examples of:
- Advertised Extra: The robot doesn't show up until the last ten minutes of the movie.
- Affably Evil: Dr. Krupp is nice enough to give Dr. Almada a belated congratulations for his wedding.
- Anti-Climax: The fight between the robot and the Aztec mummy only lasts about one and a half minutes.
- Artistic License – History: The Aztecs did not, in fact, practice mummification. note
- Awakening the Sleeping Giant: Popoca is completely harmless unless someone disturbs him. Guess what Dr. Krupp does.
- Bad People Abuse Animals: During Krupp's lengthy diatribe before he unveiled the Robot, he mentioned that he "tortured many animals, with pleasure" as part of his studies.
- Based on a Great Big Lie: The opening narration claims that the events of this movie are based on a real experiment. Naturally, there was no such true event involving a robot and an Aztec mummy.
- Cool Versus Awesome: Wellllll... it's what they were going for, anyway.
- Cyborg: Probably what they meant by "human robot". To be fair, this movie came out about two years before the term was invented.
- Damsel in Distress: Flora is pretty much this. She gets sacrificed in a past life as Xochi, gets kidnapped and hypnotized by Krupp in her present life and is made an unwilling servant of Krupp via said hypnosis, doing tasks for him while sleepwalking like a non-lethal Cesare.
- Dreaming of Times Gone By: Flora is hypnotized to remember her past life as the mummy's girlfriend, Xochi.
- Flashback: Almost the entire fricken' movie. The first half of the film consists of Dr. Almada narrating the events of the first two films in the series. The actual plot of this movie doesn't crop up until nearly the end.
- Evil Gloating: Dr. Krupp cranks up the Large Ham and give a ludicrously-long monologue about his Evil Plan and what his cyborg is capable of. It goes on waaaaay too long, which makes the Anti-Climax even more glaring.
- Holy Burns Evil: The Mummy doesn't like the sight of the cross, though he's not really evil.
- Large Ham: Dr. Krupp, big time. Like a Saturday morning cartoon villain. He must be seen to be believed.
- Horrifying Hero: Popoca, a living and violent mummy fighting against the Mad Scientist Dr. Krupp.
- Mad Scientist: Doctor "The Bat" Krupp.
- Mr. Exposition: Dr. Almada. About two thirds of the movie is a flashback that he narrates.
- Mummy: One notably based on Egyptian mummies, despite being ostensibly Aztec.
- Notary Nonsense: The very cheesy opening narration states that a notary public leaves no doubt that this movie is based on true events:Narrator: There is no doubt as to its authenticity. Testimony of people participating in the experiment, sworn to by a notary public, preclude the possibility of any fraud.
- Revenge Before Reason: Dr. Krupp finally completes his humanoid robot — his lifelong work, the whole reason he wanted the Aztec treasure to start with. He has no reason to sic it on Popoca — who has already almost killed him once — except a desire for revenge.
- Star-Crossed Lovers: Popoca and Xochi's backstory and the reason Popoca became a mummy. Xochi was a Vestal-virgin-like priestess who committed the sin of being in a romantic relationship.
- Stock Footage: Dr. Almada's recap narration is peppered with stock footage from the previous two films. And some of the stuff from the first film had already been recycled for the second film.
- The Juggernaut: Bullets have no effect on Popoca, and he makes short work of Krupp's super-strong robot. In previous films he survived a temple collapsing on him.
- Tin-Can Robot: The "human robot" is a man wearing a number of tin boxes and a bucket over his head.
- Two-Faced: As shown in the extensive flashback footage, Krupp's henchman Bruno was burned by Popoca and holds a grudge towards it for scarring half of his face.
- Useless Protagonist: Dr. Almada and Pinacate get taken prisoner the instant they find Dr. Krupp's lair. Popoca handles all the heavy lifting in the "beat the bad guy" department.
- Versus Title: The title.
