The Arabic science of cosmology has evolved for several centuries, consequently (but not too consequently) absorbing elements of the Oikumene vision from the Antiquity and the Iranian, Indian etc. cultures and layering them on the framework, set by the Holy Qur’an. Many medieval scholars of the Muslim world collected, interpreted and organized throughout their lives knowledge about the natural environment, and, particularly, described the demonic creatures, which had taken their place in the legends of Arab tribes before the advent of Islam, and then remained in the folk culture of the Islamic era due to the tradition of the oral transmission. While the religious doctrine presents only some demonic or semi-demonic creatures like the “canonic” angels, djinn and shaitans, others continued to exist in Bedouins’ memories and furthermore appeared to become objects of study in the educated urban environment. The syncretism of the Islamic cosmology has contributed in the nature of research of such creatures. Attempts to combine the pre-Islamic tradition and Qur’anic descriptions of the world along with the cosmographic elements of various cultures and those evidences about faraway lands that were reported by some merchants and travelers led to the highest degree of diversity in the description of the wondrous beings. The appearance and habits were not the only bone of contention between the scholars, the nature of such creatures also never enjoyed the unified approach. This paper seeks to explore different views about the nature of one of such wights called “nasnās” and to provide some information about the term’s etymology, the creature’s appearance, habits and origins as well as to give an attempt to organize the fragmentary data and to regulate it into some system.