The epithet Lykaios — "wolf-Zeus" — belongs to Zeus only in the context of the Lykaia, which was the main Arcadian religious festival. The name connects to Lycaon, the mythical king of Arcadia, whose story became one of Greek mythology's most disturbing: he invited the gods to a banquet and served them human flesh to test whether his guests were truly divine. Zeus overturned the table and struck down Lycaon's house with a thunderbolt. In some versions of the myth, Zeus transformed Lycaon into a wolf — an early instance of what later traditions called lycanthropy. The founding myth of the Lykaia therefore carried violence at its center: a god offended by a human transgression, and punishment swift and metamorphic. The festival seems to have retained this founding tension throughout its history.

What ancient Greeks said about the Lykaia's inner rites was always secondhand, always hedged. According to Plato, a particular clan gathered on the mountain every nine years to sacrifice to Zeus Lykaios, mixing a morsel of human entrails with the animal's portions. Whoever ate the human flesh was said to be transformed into a wolf, and could return to human form only if he abstained from human flesh for nine years thereafter. The traveler Pausanias recorded a specific story: the Olympic boxing champion Damarchus of Parrhasia had "turned into a wolf at the sacrifice to Zeus Lykaios, and changed back into a man again in the ninth year thereafter." Scholars have read this tradition as a mythologized rite of passage for adolescent males — the epheboi — in which the nine-year transformation period maps onto a period of social liminality before full adult status. No ancient writer claims to have witnessed the rite directly. The rumors were what circulated. The ritual itself stayed secret.

Several sites on the mountain were associated with the Lykaia. Near the ash altar at the summit lay a forbidden precinct — the temenos — which humans were said not to enter under any circumstances. Anyone who crossed into it would die within the year. Within the precinct, according to tradition, no creature cast a shadow, human or animal. There was also the cave of Rhea, the Kretaia, where local tradition held that Zeus was born and was tended by nymphs. A sanctuary of Pan stood nearby. The mythological geography of the mountain was dense: creation story, forbidden space, nocturnal sacrifice, and athletic games all overlaid on the same terrain. When the games later moved to Megalopolis in the 4th century BCE — when that city was founded in 371 BCE — the Arcadians continued to sacrifice on the mountaintop, keeping the older ritual alive alongside the reorganized civic festival.

The ancient Lykaia were one of four major athletic festivals of the Greek world — ranked alongside the games at Elis, Athens, and Argos in terms of antiquity, with debate among ancient writers about their precise order of institution. In 1973, the Ano Karyes Association "O Lykaios Dias" reestablished the games on the same mountain. They take place every four years, usually in early August. The modern ceremony begins with the lighting of a flame on the sacred peak by the Estiades, women who carry the Arcadian flame from the north. A head priestess recites the Lycean Ode by Pindar. A torch-bearer runs to the stadium and lights the altar. Winners receive an olive branch rather than monetary prizes — the motto is "Laurels, not prizes." The 13th modern Lykaia were held from July 31 to August 7, 2022. The games connect a living community to a tradition that is, at its core, more than five thousand years old.