Callisto

Callisto is a former Hunter of Artemis and the ex-girlfriend of the goddess. However, Zeus was attracted to Callisto and in order to get close to her, he disguised himself so as to look like his daughter. While Callisto was separated from the group, he tried to seduce her in this form. It did not work though as she tried to refute his advances, so he took her by force. Callisto would then become pregnant during this encounter and tried to keep it from showing.

Eventually, Artemis and the other Hunters discovered her condition while bathing and the goddess was furious. Though Artemis said to Callisto that it wasn't her fault, she shouldn't have lied to her. Instead of letting her go out of the Hunt in peace, Artemis turned her into a bear and told her former best friend to run, for she and the other Hunters would hunt her down if they came across her again.

Callisto (as a bear) eventually gave birth to a human son by the name of Arkas. Out of pity and/or possibly guilt for his own actions, Zeus transformed the Memory of Callisto into a constellation; the constellation which would become known as Ursa Major. Arkas almost shot his own mother with an arrow, but before he could, Zeus turned him into a bear and also set him into the stars. This time, Arkas' body itself became Ursa Minor.