A Tzitzimitl is a monstrous female skeleton related to fertility and stars in Aztec mythology.
Tzitizimitl were feared for their destructive roles in the cosmos and were believed to cause solar eclipses due to attacking the sun, they would also descend upon the Earth during such eclipses and possess men.
They would also be destined to descend onto the Earth to devour every last human if proper sacrifices were not made, while in later works they are described as "demons" this is not entirely accurate, though in all forms they are extremely dangerous entities, especially in times of cosmic turmoil.