Guinea Pig (ギニーピッグ, Ginī Piggu) is a Japanese horror (and later, black comedy) series that consists of six films, as well as two making-of documentaries.

One or more entries in the series were suspected to have influenced Tsutomu Miyazaki, a serial killer who kidnapped and murdered four young girls.

[1][2] The film depicts a group of men who kidnap and graphically torture a young woman in a variety of ways—these include hitting her, kicking her, pinching her with pliers, forcing her to endure sound torture, burning her with hot oil, pouring maggots and offal on her, hanging her up in a net, and poking a needle through one of her eyes.

[2] Guinea Pig 2: Flower of Flesh and Blood (ギニーピッグ2 血肉の華, Ginī Piggu 2: Chiniku no Hana) is a 1985 film written and directed by Hideshi Hino, based on his horror manga works, and is the second entry in the series.

The plot revolves around a man dressed as a samurai who drugs and abducts a woman, takes her to his home, dismembers her, and adds her body parts to a collection.

[3][4] It garnered controversy for its graphic content and was reportedly withdrawn from the market after being examined by a number of Japanese boards of education.

[5] It was also suspected to have influenced serial killer Tsutomu Miyazaki—also known as the Otaku Murderer—who abducted and murdered four young girls in the Saitama and Tokyo prefectures.

[16] After an introduction given by an American reporter discussing strange cases from around the world, the story begins, centering around an unlucky salaryman named Hideshi.

Though He Never Dies features graphic imagery, it is more darkly comedic in tone than its predecessors and its successors except Devil Woman Doctor.

[16][18] Guinea Pig: Mermaid in a Manhole (ギニーピッグ マンホールの中の人魚, Ginī Piggu: Manhōru no Naka no Ningyo) is a 1988[1][18][19] film written and directed by Hideshi Hino, based again on his horror manga works.

Over time, her illness gets worse, and eventually she begins suffering the symptoms of a horrendous infestation in which countless worms of various sizes burst out of the boils on her body.

[21] Guinea Pig: Android of Notre Dame (ギニーピッグ ノートルダムのアンドロイド, Ginī Piggu: Nōtorudamu no Andoroido) is a 1988[1][22] film directed by Kazuhito Kuramoto.

Guinea Pig: Devil Woman Doctor (ギニーピッグ ピーターの悪魔の女医さん, Ginī Piggu: Pītā no Akuma no Joi-san) is a 1990[1][15][16] film directed by Hajime Tabe.

[23][better source needed] According to Salvador Jimenez Murguía: "despite being chronologically labeled as the fourth in the series, [Devil Woman Doctor] is often referred to as the final [Guinea Pig] film.

[17][24][25] The film takes the form of several vignettes in which she encounters numerous patients, including a family whose heads explode if they get upset and a woman whose heart explodes when she becomes scared, a man with dissociative identity disorder who finds a new life as a street comedian, a yakuza member who has a sentient tumour with a human face growing on his stomach, and a zombie who lives a relatively normal life with his still-living girlfriend.

The first patient produces soybean paste under his feet and can spit eggs containing infant aliens from his mouth, the second has an elastic penis, the third constantly emits smoke from his body, and the fourth has a heart which moves around inside him.