Ketu

A malevolent “planet” in Hindu astrology
(jyotisha), and was originally the body
of a demon. According to the story, the
gods and the demons join forces to
churn the ocean of milk to obtain the
nectar of immortality. The gods manage
to trick the demons out of their share.
While the gods drink the nectar, the
demon Sainhikeya slips into their midst
in disguise. As the demon begins to
drink, the sun and moon alert Vishnu,
who uses his discus to cut off the
demon’s head. Sainhikeya’s two halves
become immortal, since they have come
into contact with the nectar. The severed
body becomes Ketu, and the severed
head becomes another malevolent
planet, Rahu. Ketu is not regarded as a
physical planet, but as the descending
node of the moon, or the place where it
intersects the ecliptic while passing
southward. Ketu is also associated with
comets and fiery meteors, generally
considered signs of ill omen. See
Tortoise avatar.