Dealing with spiritual creatures, even natural ones, can lead to some pretty frightening things.
- Remember the episode where the little girl's eyes were infected with mushi? Remember when she finally opened her eyes and...
- Or what about the mushi that made emotionless, fake children? Or perhaps the Mushi that re-animates corpses? Or the ones that infest your ears, make you deaf, and then kill you? Or the one that eats memories, leading to what is essentially Alzheimer's, and that is completely invisible so long as it is in shadow, so all it takes to get infected is to sit in the shade of the wrong tree?... Really, all of the mushi can be pretty horrific if you aren't careful with interacting with them.
- How about the mushi that gave prophetic dreams/made them real? Sure it started out beneficial, but then it got to the point where the dreams started happening in real life... including everyone except the dreamer being covered in green mold and crumbling away like dust.
- The concept of mushi in itself is rather disturbing - ethereal creatures which are neither animal, plant or human - and as such are so very like and unlike the world they influence in myriad ways and reasons, often simply by chance events or encounters.
- Everything about the "Cotton Spores" story. The mushi itself is creepy enough...I mean, "Hitotake"? That means "mushroom person". Arrrgh! But the reactions of the three humans in the story are almost worse. The husband's anguish, the wife's increasingly deranged behavior, and normally compassionate Ginko coldly telling a sentient mushi that he fully intends to kill it dead...brrr. Ginko carrying it off as a horrible little face in a jar is just icing on the creepy cake.
- The manga has some more Eye Scream fun that was left out of the anime. Including a story where the Tokoyami in Ginko's left eye cause him intense pain and the empty socket starts leaking eternal darkness.
- Something similiar to this did happen in the anime, to Ginko's mentor, Nui. It's how she knows the tokoyami are finally coming to claim her.
- Same with purple squicky stuff coming out of the forehead, or pink clouds from the ears and mouth.
- Or rainbows that make you hallucinate and attach to your body. That's right, even rainbows are terrifying in this story.
- Also strings that float in the sky, that are actually fishing lines for huge flying mushi to grab food with. Oh, and the "food" can be just about anything, by the way. Including humans.
- The "dog" that the boy draws in the first episode. It comes to life, still appearing as a poorly made child's drawing. To say the least, the thought of seeing something like that actually walking around gives me the willies.
- In Zoku-shou, there's an episode with a guy who can literally bring death to anything he touches with his mushi-afflicted hand. He uses this hand to hunt with, but the other villagers refuse to buy the meat because it smells rotten. At the end of the episode, his arm is devoured by the creatures of the forest.
- Episode 6 of Zoku-shou, with a family line of gardeners who are practically serial killers, who chop off heads of young girls to graft onto one mushi-infected girl found in a cherry blossom tree to keep her alive over centuries.