Films: Matango (1963)
Height/Weight: That of an average human.
Summary: When one thinks of mushrooms, they are either food to put in cuisine or sources for cheap drug jokes. In this case, they're the absolute last thing you want to encounter. If they were one of Mario's power-ups, they'd be an instant game-over.
History: Residing on an undiscovered Pacific island, the Matango were just a bunch of unnaturally large mushrooms...with a dark secret. The product of nuclear testing, the Matango had the ability to infect those who ate them. And for a shipwrecked bunch of hungry humans, that could only mean trouble...
Notable Kills: Those infected might as well be dead. You can practically see the humanity fade away with time.
Final Fate: After the majority of the people are infected and/or dead, only one escapes. But when he gets to civilization, it seems that he's been infected too...
Powers/Abilities: Upon being ingested, the Matango slowly overtakes a host until it becomes a fungal beast.
Weakness: Anything conventional.
Scariness Factor: 2.5-Creative as these things are, there's still the fact that these things are only dangerous to you if you eat them. Sure, those dumb/desperate enough to do it will be a threat, but they go down easily enough. Just show some restraint, and you'll be just fine.
Trivia: -This film almost got banned in Japan due to the early stages of the Matango-infected looking like Hiroshima burn victims. Considering how they were on the receiving end of that, how could you blame them?
-This film was based on the William Hodgson short story, "The Voice in the Night".