Their name basically means 'wild rust' or 'field rust,' and since they look like a sort of rust when they're sitting still, it's a very fitting name. Yasabi are a nearly harmless mushi. In fact, they're in many ways essential to life; in Ginko's world, they act as agents of decay, helping to break down dead bodies much like maggots or other normal bacteria do. And because this mushi exists, it's entirely likely that this is actually taking the place of many of those creatures that do the job in our world.
When a yasabi finds a meal (aka a dead body) it attaches to it, and, sending out a sound that only others of its kind--or mushishi with really good ears--can hear, it beckons more yasabi to the feast, and thus they all work together.
However, like many mushi, there is a serious problem if there are too many of them. If they have been summoned to a place without any food, they'll start attaching themselves to anything--wood, metal, even living creatures.
A person afflicted by yasabi.
They don't appear to harm living things in any permanent way when this happens, but they do slowly make it harder to move. The more yasabi you have attached to you, the more difficult it is to walk around and function as a normal person. If you can't see mushi, your skin starts to feel strangely hard without anything appearing to be the matter with it. In canon, Ginko dispersed them by using a girl who had unusual qualities to her voice. The yasabi liked her, and would travel to her when they heard it.
Though if there's no handy person with a voice like that, there's one other way to get rid of them; yasabi don't like salt and sea water. Simply going for a swim in the ocean will likely cure you.
Yasabi
Yasabi attached to a wooden post.
Their name basically means 'wild rust' or 'field rust,' and since they look like a sort of rust when they're sitting still, it's a very fitting name. Yasabi are a nearly harmless mushi. In fact, they're in many ways essential to life; in Ginko's world, they act as agents of decay, helping to break down dead bodies much like maggots or other normal bacteria do. And because this mushi exists, it's entirely likely that this is actually taking the place of many of those creatures that do the job in our world.
When a yasabi finds a meal (aka a dead body) it attaches to it, and, sending out a sound that only others of its kind--or mushishi with really good ears--can hear, it beckons more yasabi to the feast, and thus they all work together.
However, like many mushi, there is a serious problem if there are too many of them. If they have been summoned to a place without any food, they'll start attaching themselves to anything--wood, metal, even living creatures.
A person afflicted by yasabi.
They don't appear to harm living things in any permanent way when this happens, but they do slowly make it harder to move. The more yasabi you have attached to you, the more difficult it is to walk around and function as a normal person. If you can't see mushi, your skin starts to feel strangely hard without anything appearing to be the matter with it. In canon, Ginko dispersed them by using a girl who had unusual qualities to her voice. The yasabi liked her, and would travel to her when they heard it.
Though if there's no handy person with a voice like that, there's one other way to get rid of them; yasabi don't like salt and sea water. Simply going for a swim in the ocean will likely cure you.