Zeus lay with Metis but immediately feared the consequences. It had been prophesied that Metis would bear children more powerful than Zeus himself. In order to forestall these dire consequences, Zeus swallowed Metis immediately after lying with her. He was already too late: Metis immediately conceived a child. Metis immediately began making a helmet and robe for her fetal daughter. The hammering as she made the helmet caused Zeus great pain and Prometheus, Hephaestus, Hermes or Palamoan (depending on the sources examined) cleaved Zeus's head with an axe at the river Triton. Athena leaped from Zeus's head, fully grown, armed, and armored, and Zeus was none the worse for the experience.
She was also the mother of Porus.
One of the moons of the planet Jupiter was named for her in 1979.