Matango (マタンゴ) is a 1963 Japanese horror film directed by Ishirō Honda. The film stars Akira Kubo, Kumi Mizuno and Kenji Sahara. Partially based on William Hope Hodgson's short story "The Voice in the Night", it centers on a group of castaways on an island who are unwittingly altered by a local species of mutagenic mushrooms.

Matango was different from Honda's other films of the period as it explored darker themes and featured a more desolate look. Upon the film's release in Japan, it was nearly banned due to scenes that depicted characters resembling victims of the atomic bombings of Hiroshima and Nagasaki. Retrospective reviews generally commented on how the film varied from Honda's other work, with its darker tone.

The film was released directly to video in the United Kingdom as Fungus of Terror and an abridged version aired on television in the United States with the title Attack of the Mushroom People.

Quarantined in a Tokyo mental hospital, a psychology professor named Kenji Murai is visited by a group of doctors asking him about the events that led him there. Murai proceeds to explain how, despite only two of his party being dead, he was the only one to be rescued. He then relates the story of his band of day trippers on a yacht: Murai, wealthy industrialist Masafumi Kasai (the owner of the yacht), salaryman skipper Naoyuki Sakuda, his shipmate assistant Senzō Koyama, celebrity writer Etsurō Yoshida, professional singer Mami Sekiguchi, and student Akiko Sōma. A sudden storm causes the yacht to nearly capsize. Though the boat remains upright, it sustains severe damage during the storm and drifts uncontrollably. The group arrive at a seemingly deserted island and begin to explore. They come across ponds full of fresh rainwater and a forest populated by unusually-large mushrooms.

As they cross the island, they come upon a wrecked ship on the shore whose sails are rotted and its interior is covered with a mysterious mold. Murai, after reading the ship's log, warns them not to eat the mushrooms because they might be poisonous since the former crew had hallucinations after eating them. Finding that the mold is killed by cleaning products, they work to clear it from the ship. In doing so, they begin to suspect that the ship was connected to nuclear tests conducted in the vicinity of the island, with the resultant fallout forcing a bizarre mutation on various organisms native to the surrounding area, including the mushrooms. As the days pass, the group grows restless as their supply of food stores starts to run low. Kasai refuses to help find a way off the island and insists on living in the captain's quarters alone. One night, as Kasai is raiding the food stores, he is attacked by a grotesque-looking man who promptly disappears after encountering the group.

A drunk Yoshida decides to try eating the mushrooms for their hallucinogenic properties. After scuffling with Koyama over Mami, Yoshida pulls a gun and declares his intent to have his way with the women after murdering the others (accepting that if the mushrooms do turn him into a monster, then there will be no consequences for his actions). Subdued by the others, Yoshida is locked in the captain's quarters, ironically ousting Kasai. Kasai tries to convince Naoyuki to abscond together with the food and repaired yacht. Naoyuki violently rebukes this notion, but an unstated amount of time later hogties Kasai and flees with all the gathered food (including Koyama's secret stash that they had been hoarding to extort money from Kasai). Faced with this dire prospect, Mami frees Yoshida and they attempt to take over the ship, shooting and killing Senzō in the process. Murai and Kasai manage to take the gun from Yoshida and force the two off the ship. Some time later, Kasai is confronted by Mami, who entices him to follow her into the forest and eat the mushrooms. Perpetual rainfall has caused wild fungal growth, and Kasai realizes that those who have been eating the mushrooms have turned into humanoid mushroom creatures themselves. The mushrooms are delicious and cannot be resisted after the first bite. Kasai eats the mushrooms, hallucinates scenes of Tokyo nightlife, and falls to his knees amongst the creatures.

Murai finds the yacht adrift and swims out towards it. He finds a note left behind by Naoyuki listing the names of those on the island as dead and how, having now run out of food and energy, he has decided to jump into the sea. Murai draws a large X over the note. Others who have turned into mushroom creatures attack Akiko and Murai. They are separated and Akiko is kidnapped. As Murai tracks her down, he discovers that she has been fed mushrooms and is under their influence along with Mami, Yoshida, and Kasai. Murai attempts to rescue Akiko, but he is overwhelmed by the mushroom creatures and flees without her, making his way onto the yacht and escaping the island. Several days pass later, Murai is finally rescued. As he waits in the hospital, he begins to wonder if he should have stayed with Akiko on the island. His face is revealed to show signs of being infected with fungal growths. Murai states after that it did not matter whether he stayed or not, but he would have been happier there with Akiko. The screen fades as Murai notes that humans are not much different from the mushroom creatures.

The film was based on a story in S-F Magazine which Masami Fukushima was an editor of. A treatment was written on the film by Shinichi Hoshi and Fukushima which was then made into a screenplay by Takeshi Kimura. The story itself was based on William Hope Hodgson's short story "The Voice in the Night", which originally appeared in the November 1907 issue of Blue Book.