''The Deadly Mantis'' is a 1956 American film concerning the then-popular mutation and animation of a giant beast, usually prehistoric. In this case, the beast is the eponymous mantis, loosed in the opening sequence of the movie, where it proceeds to destroy many things, progressively eating more people, until an ace pilot accidentally rams the mantis with his jet, forcing it to the ground and kills it. Interwoven into this tale is a romantic subplot involving the photographer Miss Blake and Colonel Joe Parkman, the Ace.

For the ''Series/MysteryScienceTheater3000'' version, please go to the [[Recap/MysteryScienceTheater3000S08E04TheDeadlyMantis episode recap page]].

!!''The Deadly Mantis'' contains the following tropes:

* TheAce: Colonel Joe. He does screw up when he loses sight of the mantis and then collides with it, but it does force the mantis to the ground.
* AllMenArePerverts: The entire Arctic base moons over moderately attractive Marge. Justified in that they've been isolated for months and they're even at a hop dancing with ''each other''.
* ArtisticLicenseBiology: "Every known species of animal has a bony skeleton." What?![[note]]He probably meant mammal, since he mentions reptiles as also having bony skeletons, so he thinks they're not whatever he means by animal.[[/note]]
* {{Attack Of The 50 Foot Whatever}}: Prehistoric this time, rather than [[ILoveNuclearPower atomic]].
* ButterflyOfDoom: Mentioned in the opening spiel as the cause for the Deadly Mantis' parole on ice --- then it is shown to be a ''volcano''.
* CassandraTruth: Marge asks Nedrick why the Pentagon wants him. He tells her that they want him to study an old bone they found in the Arctic. She thinks he's being evasive -- then finds out he was telling the truth.
* DecoyProtagonist: [[ZigZaggingTrope Zig-zagged]]; the beginning of the film follows Col. Joe as he investigates a couple of "incidents" caused by the Deadly Mantis; then the focus shifts to museum curator (and Insect Expert) Nedrick Jackson, who appears to take over the lead role... right up until he, [[SatelliteLoveInterest Miss Blake]] and Col. Joe return from the Arctic to track the big bug in New York City, at which time Col. Joe hops back into the driver's seat.
* DevelopingDoomedCharacters: Played with the twist that the monster does appear at the very beginning of the film, but there's a lot of scenes in offices later.
* DirtyCoward: One of the tribesmen abandons another that's trapped when the mantis attacks.
* InfoDump: There are lengthy narrations about map locations and the early warning radar picket lines.
* MisplacedAccent: Why does a Canadian Air Force officer have a "Tally Ho!" British accent?[[note]]There are many Brit-accented Canadians taking after the old colonial power, but this probably wasn't what they were going for.[[/note]]
* SlayingMantis: The title says it all.
* StockFootage: The assembly of North American early warning radar picket lines, which ultimately have nothing to do with the plot other than to establish the location.
* StockSoundEffect: The roars of the mantis, especially the ''"MMMUROOOAAAARRROOOOOAAAAARRR"'' bellow, went on to be the roars of many giant beasts, including Bruce #4 in ''Film/JawsTheRevenge''.
* YouNeedToGetLaid: The entire Arctic base, in fact.