Jiger is a horned quadrupedal reptile somewhat reminiscent of the extinct dinosaur Triceratops. Unlike Triceratops, however, Jiger has a dorsal sail, two nose horns and a single forehead horn.
After workers from the World's Fair remove a statue embedded in an island, Jiger makes her first appearance and immediately gains Gamera's attention. The first of several fights ensues, resulting in a victory for Jiger through her use of the projectile quills in her face. The quills impale Gamera's arms and legs, knocking him onto his back and preventing movement. Furthermore, the quills pierce the limbs in such a manner that Gamera is unable to withdraw his limbs into his shell and take flight. This frees up Jiger to continue her pursuit of the statue, which is making a horrible ringing sound that causes her tremendous pain.
Jiger lets nothing impede the hunt for the statue, splitting two ships in half before tearing through Osaka in pursuit. In the midst of chase, Jiger displays another weapon: a heat ray capable of vaporizing not only flesh, but entire city blocks. The J.S.D.F. makes a tentative effort to kill the monster through deployment of F-104 fighters, but they are promptly shot down with her quills and the deployment is brought to a halt.
Eventually, Gamera makes his return, having freed himself from the quill trap. He proceeds to engage in combat with Jiger, appearing to have the upper hand until Jiger pulls Gamera in close. Upon securing her grip, Jiger extends a stinger from her tail and inserts the barb into Gamera's chest, laying an egg inside his lung; this prompts Gamera to retreat back to the bay, where his body takes on a chalk white color reminiscent of ice. With her opponent presumably indisposed, Jiger heads directly to the World's Fair, where she finally manages to acquire the statue. Upon successfully locating her target, Jiger proceeds to throw it into the ocean, silencing the painful ringing. Gamera is presumed to have been killed at this point as Jiger heads straight to the World's Fair. Jiger finally obtains her goal of the statue, and throws it into the ocean, ending the painful noise.
The scientists were checking out possible causes of the noise, as it affected humans, causing temporary insanity. The children convinced them to do a medical exam on the comatose Gamera, where it's discovered that there's a dark spot on one of his lungs. One of the scientists served as a zoo director and realized that the spot might not be a fast spreading cancer, but actually a Baby Jiger growing in Gamera's lung. An operation was needed to remove the threat, so the children took the initiative by taking a walkie talkie and a mini-sub. Communication is established with the kids and they enter Gamera through his open mouth, and after almost going into his stomach, they arrive at the problem lung. The children are able to exit the sub and walk around in the lung. There, they discover the baby.
The baby looks like its mother, except that instead of shooting quills, the baby squirts sticky goo. But, the baby has a weakness just like its mother: white noise. The kids discover this is actually a fatal weakness and manage to kill the baby using static from their radio. They leave Gamera's body and report their findings to the scientists. They rig up large speakers to keep Jiger at bay, as well as figuring out that power would have to also be run into Gamera, who cannot recover on his own. The children make a final trip inside Gamera to hook up a set of power lines directly to his heart.
Jiger is kept still by the speakers playing the white noise. It's not enough to kill Jiger, but buys enough time for the other plan to start. Gamera is subjected to high voltage shock before the electrical grid overloads. It's enough that Gamera revives on his own.
Gamera flies over to the World's Fair for the final battle. Jiger tries every weapon she's got, but Gamera merely retracts into his shell when the quills start flying. Jiger then uses her heat ray. It doesn't affect Gamera's shell or even skin. Gamera body-slams Jiger several times from great heights, but Jiger isn't really affected. However, it buys Gamera the time needed to go into the ocean to retrieve the statue from the sea floor. Jiger, enraged by the statue's return attempts to impregnate Gamera again. Gamera uses the statue to crush Jiger's tail, destroying the stinger. Gamera taunts Jiger with the statue, who tries in vain to catch Gamera and retrieve the statue. Gamera finally ends the fight by throwing the statue at Jiger, which embeds itself in Jiger's skull, killing her.
Solid Saliva Missiles:
Jiger can shoot deadly saliva-compacted quills from the corner of both sides of the nose known as the Solid Saliva Missiles (唾液固形ミサイル/Daeki Kokei Misairu), whioch stop Gamera's movements by skewing his hands and feet with those quills, making it impossible for Gamera to retract into his shell.
She can also fly by means of jets in the back of her head.
Jiger fires an Ultrahigh frecuency ray in the shape of a curve from a single corner of her head, known as the Magnetium Beam (マグネチューム光線/Magunechyumu Kosen) that is capable of dissolving buildings and ships and even people till the bones.
Jiger possesses a needle or stinger of the fallopian tube at the end of the tip of her tail. Despite not being actually venomous, the stinger is used by Jiger to reproduce in ways similar to insects, in that it can be used like an ovipositor to implant an egg into a victim that feeds off the victim's blood when it hatches, and this ability is known as Bloodsucking Strategy (吸血戦法/Kyuketsu Senpo). In addition, Jiger can put her eggs inside other creatures, such as Gamera, which parasitically lives off the host up until it hatches. And from the fact that it's effects make the head and arms or fron legs from her victims like Gamera to be seen through, it is also known as the Transparent Strategy (スケスケ戦法/Sukesuke Senpo).
Jiger has a suction ability provided on the back of both fore and aft feet known as Magnetic Sucker (マグネチック吸盤/Magunechikku Kyūban) which is one million times the suction power of a vacuum cleaner, and it lets her to pull objects to her and draw away from her too. A similar ability is called Certain Kill Air Rotation Throw (必殺空中回転投げ/Hissatsu Kūchū Kaiten'nage) when Jiger throws onto Gamera's shell before injecting her needle or stinger on him.
Jiger can not stand the Devil's Whistle and it causes her great pain. The statue was specifically built to keep Jiger at bay.
- Main article: Jiger/Gallery.
- Jiger is the first female monster in the Gamera series.
- The way Jiger implants a parasitic egg inside a living host is reminescent of parasitoid wasps, as well as the Xenomorphs from the film Alien.
- Jiger makes a cameo appearance in a Franklin the Turtle episode, along with some other Gamera villains when Franklin is imagining monsters in the dark.
- A similar event occurs in the movie Pacific Rim, where a team is sent inside a kaiju's body and ends up being attacked by a baby kaiju located inside.