The film was partially based on William H. Hodgson's short story "The Voice in the Night". The film was initially going to be banned in Japan due to the special effects on some of the mutated humans resembling the victims of the atomic bombings of Hiroshima and Nagasaki. The film was released theatrically in the United Kingdom and directly to television in the United States in shortened forms. It was released in its original full-length form on DVD in 2005 in the United States.
In Tokyo, a man travels to visit university professor Kenji (Akira Kubo) who is being held in the psychiatric ward of a hospital. He tells the man that what happened to him sounds crazy, but that he is actually not insane.
A Japanese yacht on a day trip encounters a nasty storm that nearly capsizes it. The crew and passengers include Kenji; skipper Naoyuki (Hiroshi Koizumi); his shipmate assistant Senzô (Kenji Sahara); writer Etsurô Yoshida (Hiroshi Tachikawa); celebrity Masafumi Kasai (Yoshio Tsuchiya), the owner of the yacht; and two female passengers, professional singer Mami (Kumi Mizuno) and student Akiko (Miki Yashiro). The storm leaves their ship in ruin. Without a rudder or sails to steer by, they are forced adrift. A few days after hearing a radio announcement that they were lost at sea, the group arrive at a seemingly deserted island. After spending a day in search of food and water, they come across ponds that seem man-made, full of fresh rain water, along with a seemingly endless forest of mushrooms. However, Naoyuki warns them not to eat the mushrooms, as they may be poisonous.
As they cross the island, they come across a shipwreck on the shore. Although it seems to have only been there about a year, the sails are rotted and the ship's interior is covered with a mysterious fungus and mold that has spread throughout the ship. Noticing that the mold succumbs to strong cleansing products, they work to clear it from the ship. In doing so, they begin to suspect that the ship had been involved in some sort of nuclear testing of the polluted waters, forcing gross mutations on various objects, including mushrooms. As the days pass, the group begins to grow restless as their supply of food stores start to run low. They try to acquire turtle eggs and birds, though this proves difficult, as birds seem to actively avoid the island. With Kasai refusing to help find a way off the island and instead stealing from the food stores, Yoshida begins to get edgy, eventually eating the mushrooms on the island instead of eating the potatoes and seaweed they are able to find to sustain themselves.
One night, as Kasai is raiding the food stores, he is attacked by a grotesque-looking man who promptly disappears after encountering the group, leading them to believe that something is very wrong with the island. Shortly after Yoshida and Kasai fight over Mami's affections, Yoshida goes crazy as a direct result of the mushrooms' influence. He pulls a gun on the men, but is locked in Kasai's room. Naoyuki decides that they must leave the island in order to survive, but the others disagree, so he departs on his own. Mami frees Yoshida and they attempt to take over the ship, shooting and killing Senzô in the process. Kenji and Akiko manage to wrest control from them and force them off the ship. Kasai travels out to the yacht only to find Naoyuki missing and a note left behind, explaining that Naoyuki is responsible for the deaths of the group and that he has jumped overboard. On his way back, Kasai is confronted by Mami, who entices him to follow her into the forest. Perpetual rainfall had caused wild fungal growth, and Kasai realizes that those who had been eating the mushrooms turned into mushrooms themselves. Due to its addictive nature, no one can escape the mushrooms once they take a bite. Kasai is last seen collapsing as mushroom beings swarm him.
Meanwhile, Akiko and Kenji are attacked in force by the mushroom people. They are separated and Akiko is kidnapped. As Kenji tracks her down, he discovers that she has been fed mushrooms and is under their influence along with Mami, Yoshida and Kasai. Kenji attempts to rescue Akiko, but he is overwhelmed by the mushrooms and flees without her, making his way onto the yacht and escaping the island.
Several days pass before Kenji is finally rescued. As he waits, he begins to wonder if he should have stayed with Akiko on the island. He turns toward the audience, his face covered in fungal growth, and states that it wouldn't have made a difference if he had stayed or not, but he would have been happier there with his love. The screen fades as Kenji notes that humans are not much different than the mushroom people, and the camera pans over a night-lit Tokyo.Akira Kubo as Professor Kenji Murai
Kumi Mizuno as Mami Sekiguchi
Kenji Sahara as Senzō Koyama
Hiroshi Tachikawa as Etsurō Yoshida
Yoshio Tsuchiya as Masafumi Kasai
Hiroshi Koizumi as Naoyuki Sakuda
Miki Yashiro as Akiko Sōma
Director Ishiro Honda was better known for his kaiju (giant monster) films, but occasionally developed horror films such as The H-Man (1958) and The Human Vapor (1960), where characters become bizarre transformed beings. Honda's last film in this form was Matango.
Matango's screenplay was written by Takeshi Kimura, from a treatment by Shinichi Hoshi and Masami Fukushima of science fiction magazine editor Fukushima's story, which itself was based on William H. Hodgson's short story "The Voice in the Night", which originally appeared in the November 1907 issue of Blue Book. The script was relatively faithful to "The Voice in the Night", with a significant change being the addition of extra characters.
The film was produced by Tomoyuki Tanaka, with music by Sadao Bekku and cinematography by Hajime Koizumi.
Bill Cooke noted in Video Watchdog that Matango defies easy categorization as a film belonging to either the kaiju (monster) or kaidan (ghost) genres of the era. In his book Japanese Science Fiction, Fantasy, and Horror Films, Stuart Galbraith IV described it as a psychological horror film that "contains science fiction elements".
Matango was released in Japan on August 11, 1963, distributed by Toho. In the United States, the film was released under the title Attack of the Mushroom People. Matango was nearly banned in Japan due to some of the makeup resembling the facial disfigurements characteristic of those who survived atomic bombings of Hiroshima and Nagasaki.
It was never released theatrically in the United States, but was released directly to television by American International Television (AIP-TV) in 1965. This version of the film runs at 88 minutes. Toho produced an English-dubbed version of the film, but any release of it cannot be determined.
Prior to Matango's release on home video, Galbraith noted that the film was shown frequently on American television during the 1960s and 1970s, but as of 1994, it "ha[d] all but disappeared today". The film was released on home video in the United Kingdom in the 1980s under the title Fungus of Terror. Matango was issued on DVD by Media Blasters in the United States on March 15, 2005. The DVD featured a generous selection of extras, including commentary by the film's male lead, Kubo; production sketches; an interview with special effects team member Teruyoshi Nakano; and other features. Tim Lucas (Sight & Sound) described Tokyo Shock's release of the film as "a revelation to those of us who grew up watching pan-and-scanned, re-edited bastardisations of these films on television". Lucas also noted that "Matango looks splendid on Tokyo Shock's disc, its anamorphic transfer retaining the naturalistic colour of the earlier Toho Video laserdisc release with brighter contrast and a slightly more generous (2.53:1) screen width", and that "the English subtitles access adult dimensions of the story that were never apparent in the old television prints".
In a contemporary review, the Monthly Film Bulletin reviewed an 89-minute English dub of the film. The review noted that the film was "not one of the best of Toho's special effect exercises though the mushroom people are quite fanciful and the mushrooms come in all shapes, sizes and colours", and that most scenes were "disappointingly dull" as "the whole thing sags miserably in the middle when characters get down to bickering among themselves".
Matango has been described as a "virtually unknown film", except to "aficionados of Asian cult cinema, fans of Weird literature, and sleepless consumers of late-night television programming". The film has received relatively little scholarly attention. Galbraith described Matango as one of Toho's "most atypical and interesting films". He noted that the film was not as strong as its source story, and that the creatures in their final form were "rubbery and unconvincing", but that the film was "one of the most atmospheric horror films to ever come out of Japan". In another retrospective review, Lucas stated that the film was the best of Honda's non-kaiju-themed horror films, and that it was a "well-crafted picture that parallels 1956's Invasion of the Body Snatchers". Cooke described the film as "a classic from Japan's early-Sixties horror boom" and as "some of the finest work of Ishiro Honda". He also opined that the film was one of Toho's "most colorful science-fiction productions" with a "rich and varied palette".
Actor Kubo declared that of the few monster or outer space-themed films which he acted in, Matango was his favorite.