In Greek mythology, what did the Graeae share among themselves when Perseus confronted them?

In Greek mythology, the Graeae shared one eye and one tooth among themselves.

The Graeae were three aged sisters—Deino, Enyo, and Pemphredo—born to the sea deities Phorcys and Ceto. Their name is commonly connected with old age, and they were traditionally described as gray-haired from birth.

Their single eye and single tooth passed from sister to sister as needed. Perseus exploited this arrangement during his search for Medusa and the other Gorgons, taking possession of the shared object to obtain information from them.

The Graeae are sometimes mistakenly grouped together with the Gorgons because both groups appear in the Perseus cycle and share the same parents. In the myths, however, the Graeae are distinct sisters with a strange shared set of features, while Medusa, Stheno, and Euryale are the Gorgons.