The seventh installment of the Showa-era '''Franchise/{{Gamera}}''' films. Earth is invaded by inhabitants of the planet Zigra, a water breathing race that wants to use humankind as a food source. Its up to Gamera and a handful of children in the thick of it to save the day. Daiei Studios filed for bankruptcy shortly after the release of this film, leading to a nine-year hiatus until the eighth and final Showa Gamera film would be released.

This is one of nine films to be used twice on ''Series/MysteryScienceTheater3000'' once on the local Minneapolis UHF station KTMA in 1988 during the local run of the show and later when running nationally on Creator/ComedyCentral. For those versions please go to the [[Recap/MysteryScienceTheater3000S03E16GameraVsZigra episode recap page]].

!!This film provides examples of:
* AbsurdlySharpBlade / SpikesOfVillainy: Zigra
* AlienInvasion: The planet Zigra wants to take over Earth to use humans for food.
* ArtisticLicensePhysics: Gamera breathes fire '''underwater'''.
* BlatantLies: Lora Lee chases the children with the clear intent to kill them, all the while shouting, "Come back! I won't hurt you!"
* BrainwashedAndCrazy: [[spoiler:Zigra's henchwoman Lora Lee]], as it turns out.
* DisneyDeath: Gamera gets one, [[OnceAnEpisode naturally]]; but also [[spoiler:the crew of the bathysphere]].
* EverythingIsAnInstrument: [[spoiler:Even Zigra's beached corpse]]
* [[ThreateningShark Everything's Even Worse With Sharks]]: The aquatic aliens from planet Zigra resemble sharks.
* FlyingSaucer
* GreenAesop[=/=]FantasticAesop: Don't pollute the oceans, or Space Sharks will come down and eat us all!
* HumiliationConga: [[spoiler:In between being defeated and being roasted to death, Zigra gets ''played like a musical instrument.'']]
* KillItWithFire
* LightningCanDoAnything: including [[spoiler:reviving a giant turtle.]]
* MissingMom: Helen's mom is said to be in a New York hospital.
* MsFanservice: Lora spends a few minutes in a skimpy two-piece bikini, and the rest of the movie in a T-shirt and very short miniskirt.
* MuggedForDisguise: Lora uses her hypnosis abilities to steal a bikini from a trio of pearl divers, and later a more sensible outfit from a fleeing woman.
* NamesTheSame: The monster Zigra comes from the planet Zigra.
* ParentService: The Zigra minion Lora Lee is introduced wearing form fitting SpaceClothes before switching to a bikini in an attempt to blend in with humans, finally settling on a mini skirt for the remainder of the film.
* ThemeTuneCameo: Gamera plays his own theme music, using Zigra's fins as a xylophone.