The Nymph Turned Bear
Callisto is one of Artemis's companions, bound like the rest of them to lifelong chastity. Apollodorus records that Zeus approaches her disguised as Artemis (in some copies, as Apollo) and the pretense collapses into assault; Zeus himself then transforms her into a bear to hide the affair from Hera, and Artemis, in one of the variants Apollodorus records, later kills the bear while hunting without recognizing her.