The human spirit is very restless. When a man is sleeping the spirit exits the body and walks away. The man dreams where the spirit goes, and when it returns into the body, the sudden energy surge wakes the man up. The spirit in Bosnian mythology is described as an etheric apparition which squeals. As for the soul, so as for the human spirit a bridge represents a very strong barrier and prevents it from further movement, namely, as soon as the spirit comes across a bridge during his nightly travels, he cannot cross it, it gets restless starts squealing and screaming. If someone would catch that mouse, the sleeper whose spirit is represented by the mouse would die immediately.
In Bosnian mythological representation a bridge is a notion of a place with high energy, which besides connecting two shores in the material level, on the spiritual it has the meaning of a spiritual portal through which the soul passes or perishes on its journey.
According to belief from south-eastern part of Bosnia a child's spirit is especially restless, like the child itself, it is restless and always in the mood for movement and games. Aware of this older women still today warn young mothers when moving a sleeping child from one place to another or if waking it to do it carefully, calling him by his name and pulling it lightly by the nose. If the child is a heavy sleeper they would imitate the sound of a mouse (cccc) in order to draw attention to the wandering spirit, this would force him back into the body. Otherwise, if the child would awake and the spirit hasn't returned, they would risk the child would fall ill mentally and physically.
Also for an adult the same rule applies, it should not awake suddenly, since its spirit is far away, traveling across the world. Apparently such a person could physically attack, start kicking the person that is awaking him at such an unpleasant moment. In that case it is necessary for such a person to be taken to the place where he is sleeping, for it to lie there again, and stay there until it awakes. If this is not done, the person could have some mental issues all its life.
As it is narrated among the Bosnian folk, according to the Bogomil principles, the human spirit belongs to the god of evil and the soul to the god of good. This is why it is believed that witches and wizards have to sell their souls to Iblis or some other ranked Jinn, in order to engage in magical practice and rule the unseen forces. They perform this with a ritual, usually by bringing the holly book Qur'an inside the bathroom and urinating or defecating on it. This is why the soul was purposefully exchanged for a certain power, the soul is trapped and no longer belongs to the human.
After such a situation and the disturbance of the equilibrium of good and evil, the human spirit in the body of the witch or wizard becomes extremely powerful but also evil and is capable of making various evil deeds. While the witch is sleeping, the spirit exits her, and the body gets a blue hue and becomes cold, almost as if she died, which is the consequence of a trapped soul. Her mouth gaps open and become black.
It is considered that a spirit of a common man is capable of doing bad things during its nightly travels, such as attacking someone along the way, but this spirit like the witches spirit avoids crossing over all bridges which it encounters.
Similar belief exits in Iranian - Arabic occultism where it is claimed that every human possesses its astral doppelganger. Haamzad or Qarin is the name for the Jinn which follows the man at all times and tries to influence negatively his conscious and his behaviour. Qarin is the only Jinn which cannot be destroyed with exorcism or in any other way.