Scorpion
The scorpion is, not least in astrology, associated with death and rebirth. There is an ancient belief that it kills itself if surrounded by fire. It shares certain qualities with the Phoenix on one hand, and with the serpent on the other.
It is a poisonous monster with two horns and a stinger, which was, of course, feared in places such as Africa, where it was often referred to by euphemisms. It always has its stinger ready and visible, and was seen as the embodiment of evil.
At the same time, the scorpion is unexpectedly associated with motherhood (the Egyptian goddess Hedetet was depicted with a scorpion head and a child in her arms, and the fertility goddess Serket was originally a "scorpion goddess," etc.). There was a legend that told how scorpion babies eat their way out of their mother’s body, representing the mother’s sacrifices for her children.
The alchemists had the belief that the scorpion stings itself and kills itself with its stinger; they sometimes used the scorpion as a synonym for the secret substance. The poison it is associated with could kill, but it was also "the good poison."