Later they became regarded as chthonic Underworld deities. The myths associating the underworld chthonic deities and fertility were not exclusive. Typhon is thus the chthonic figuration of volcanic forces. Hecate has been characterized as a pre-Olympian chthonic goddess. Dark animals were typically offered to chthonic deities. The serpent is worshiped as a chthonic and water deity. All these elements betoken the rites owed to a chthonic deity. As a primeval chthonic deity, Tatenen was identified with creation. Sea gods may be included with chthonic deities or form a separate, third category. The epithets of Persephone reveal her double function as chthonic (underworld) and vegetation goddess. Black was the appropriate colour for offerings to chthonic deities. Nocturnal ritual sacrifice was a common practice in many chthonic cults. In Sparta, she was known as Demeter-Chthonia (chthonic Demeter). In some forms Hades appears with his chthonic horses. Hermes began as a god with strong chthonic, or underworld, associations.