Watahiko  

In episode 21, "Cotton Changeling," Watahiko makes his appearance. Born as a green goo to Aki and Yasuke, he was later found as a baby after disappearing. This pattern continued with more identical babies being born, all named Watahiko. The truth is that Watahiko is actually a type of fungal mushi that resides within the body of a pregnant woman, replacing the embryo and forming a base near the home it was born. After birth, this fungus creates children to gather energy for itself, similar to how plant roots absorb nutrients. These children share a collective consciousness, meaning they learn from one another and communicate as effectively as older individuals. They grow at an astonishing rate, almost as quickly as bamboo. Even the youngest of these children possess the ability to communicate with others through their shared hive mind. At some point in their lives, they become ill and release spores that develop into more base-like fungi. If exposed to fire, the base transforms and the children vanish.