Gorgons

The gorgons are the daughters of the sea god, phorcys. The three gorgons names
are Medusa, Stheno, and Euryale. Medusa means to be a ruler or queen. Euryale means to be wide-leaping. Stheno means to be very strong. They all had the power to turn everyone into stone that looked at them. A gorgon is a monster in the underworld. Euryale and Stheno where immortal but Medusa was not. Their hair was replaced with snakes.
Source:
http://www.theoi.com/greek-mythology/olympian-gods.html
https://www.greekmy