Flubs are endemic to movies and television programs of all ilks! Some are continuity errors caused by multiple shooting days. Some are so-called "revealing" errors where background props, crew members' hands, and the like are visible. Others are simple mistakes made by actors scrambling their lines. And, yet others are inconsistencies in fact and logic. Herewith are some intriguing examples from entries in the sci-fi/horror genre.
-- The Day Earth Stood Still (1950)
In order to demonstrate the superior power of the ETs, the alien emissary Klaatu (Michael Rennie) had all electrical and other forms of power on terra firma cease operating(except for vitally needed uses, such as in hospitals and airplanes). That is the origin of the title, where our planet did not physically stop rotating, but only metaphorically froze, and not for a day, but only 30 minutes, from noon to 12:30 p.m.
However, while the elevator car Klaatu and the heroine, Helen Benson (Patricia Neal), were in abruptly halted, the light inside it, in a serious contradiction, remained on. Theoretically, we should have seen them conversing in total darkness! And, in various scenes depicting this global standstill, several exceptions were observable, such as a Coca Cola sign still flashing, a car moving in the background, and a barge motoring down the Thames River.
And, while Klaatu noted that he learned our language by monitoring radio transmissions, that certainly did not explain how he could jot down a perfect handwritten note in English to Professor Barnhardt (the Einstein clone portrayed by Sam Jaffe). Indeed, this may be the only instance where an ET on earth actually wrote any type of message in English!
Ruehl Fact: Patricia Neal, heroine of this film, soon thereafter co-starred in a very weak version of it, 1954's Stranger From Venus, in which the pinnacle scene was the extraterrestrial ambassador (Helmut Dantine) reading a newspaper article in five different languages!
-- Curse of the Demon (1957)
Skeptical psychologist Professor John Holden (Dana Andrews) has flown to England to debunk paranormal claims at a conference. But, at the British Museum, a leading satanist, Dr.Julian Karswell (Niall MacGinnis), has slipped a runic parchment in among his papers decreeing his death within three days. When he first discovers the parchment (actually a strip of paper), there are clearly two rows of runic symbols imprinted upon it, yet moments later, as this supernatural document flies out of his hand and tries to climb over a grating into the fireplace to be burned, ensuring the prof's demise, there is only a single row of runes!
Of course, Holden is able to wrest it before it burns. In a later scene at Stonehenge, the parchment again is shown with only one line of runes.
Ultimately, on a train, Holden passes it back to Karswell who chases after it along train tracks before it disintegrates, after which he is decimated by a demonic entity.
Considering the parchment's crucial importance to the plot line, a degree of consistency with respect to it should have been maintained.
Ruehl Fact: Director Jacques Tourneur was furious that producer Hal Chester inserted a titanic four-horned demonic creature into the opening and ending scenes, arguing that the audience members should be allowed to use their imagination to conjure up whatever monster they might envision. However, we sci-fi and horror buffs want to see the ultradimensional entities, not just imagine them, and this one was actually quite visually engaging!
-- Nosferatu (1922)
In a contradiction to vampiric lore, the reflection of the vampire Orlok (portrayed by Max Schreck) was clearly visible in a mirror after biting the heroine on the neck in a scene near the end of the film. Although based on Dracula, that name was never employed because the producers had failed to pay for the rights to use it!
Ruehl Fact: Bela Lugosi as Dracula was similarly seen in a mirror biting a female doctor (Lenore Aubert as Dr. Sandra Mornay) in 1948's Abbott and Costello Meet Frankenstein. This oversight was absolutely inexcusable, considering the emphasis placed on the lack of vampiric reflections in mirrors in the studio's initial Dracula in 1931!
Video sampler of the Nosferatu flub: