Pikochū

The Pikochū (ピコ蟲) are a hybrid breed of beetle-like insects created by Takumi Aburame. Takumi bread the Nano-Sized, Venomous Insects and the Kikaichū to make this breed of very tiny insects that are even smaller then the Nano-Sized Venomous Insects. Because of their size, they cannot be seen by the naked eye, nor can their chakra signatures be seen or sensed. They only time the insects can be seen by a dojutsu is when they are clustered, but that almost never happenes. These insects a bread inside of Takumi and live with the Kikaichuu and Nano Sized Insects

Overview
These beetles are relativity rare, they cannot fly so they are carried by 1 out of ever 10000 kikaichuu, and their presence are even rarer when carried by the Nano Sized Insects. These insects cannot fly, so they are carried on the back of the kikaichuu and when the kikaichuu land on a target, the Pikochuu are then dropped off. Kikaichuu that carry the pikochuu carry from 20 to 60 at a time which is more than enough for their abilities to take action. The Pikochuu breed very rapidly, but also die rapidly as well, if they don't find a host to use their ability then they die within less than 1 week of being born. They are born in the hundreds from just two but are eaten by the Kikaichuu, Nano Sized Insects, and their own kind. The Pikochuu's eggs are even smaller than a full sized pikochuu, but upon birth they instantly grow to their full but small size.

Function
Because they are so small, when they land on an organism say a human, they are small enough to fit and borrow through the pores of that organisms skin. This is usually as soon as they land on an organism, they take action. Once inside an organism, they find another Pikochuu and mate which only takes a few seconds. After they mate the new pikochuu are nearly instantly born and they spread throughout the whole body, but unlike inside the host they do not die so easily because they are not exposed to the many other dangers inside of Takumi's body. By the time the Pikochuu start to spread throughout the body of the organism, their numbers are in the thousands. They mainly spread through the body from their organism's veins and vessels. When they start to spread, naturally the organism's immune system starts to react and kill the foreign body, but the only problem is, the Pikochuu also start to mate again in the veins and vessels. When that happens, the immune system can't fight all those foreign bodies and accept the Pikochuu as just another part of the organisms body. By this time, the Pikochuu are in the near millions, but this is only depending on how many land on the organism when the Pikochuu are transfered from the Kikaichuu. This function only takes about 5 to 10 minutes to complete.

Once accepted by the body, the Pikochuu go to work; their whole function is to infiltrate and control, and the whole nerve system of any living breathing organism is the brain. The Pikochuu immediately go for the brain, once inside the brain they eat the nerve of the brain and replace that nerve with themselves by spreading what chakra they have to replace that nerve. Also, yet again, when the Pikochuu reach the brain, they mate, but they keep on mating because of how many nerves the brain of a certain organism has. Some organisms it doesn't take that long for the Pikochuu to take control of the brain, but when they do, the organism is essentially brain dead. Once all the nerves have been eaten and replaced, whatever new nerve formed will be the Pikochuu's. But it all comes back to Takumi, when this happens Takumi can control that person for as long as he wants as the Pikochuu also keep on mating and spread throughout the whole body for an even more absolute control.

The Pikochuu can also eat the nerves on other part of the organism's body at the command of Takumi. It takes the course of an hour to perform their function in the brain, but the organism(if mainly human) can possibly negate the function of the Pikochuu. If the Pikochuu have already infiltrated the opponent body, they organism can simply run chakra through the certain part, or parts of the body to kill off the Pikochuu. Another way to tell if they have infiltrated the organism's body is the organism forgets things when their nerves are being eaten. Though it starts with simple things like things that are usually not memorized by the organism, then the organism gradually forgets things it remembers like jutsu, hand signs, words, etc. Then that gets worst as they forget their name, where they are, personality, etc, by this time it is usually too late for the organism.

No one else can harbor the Pikochuu in their body but Takumi unless special circumstances, if another person tries to harbor these insects the pikochuu's process will only carry on to that person.