Amphora of Attic production (about 530-520 B.C.), representing the mask of Dionysus, now in the National Museum (Museo Nazionale Tarquiniense), Tarquinia, Italy.
Unlike the other gods, Dionysus is sometimes represented in a frontal way, with his eyes looking directly into those of the beholder. Just this representation leads to better understand the unavoidable power of his look, which induces the abolition of the barriers which generally separate the human from the divine, thus permitting an interpenetration of the worshipers and the gods. Around him, Maenads in an ecstatic trance, Satyrs, Centaurs and Sileni move excitedly, expressing with somersaults and jumps their joyous and discharging frenzy, obscuring in this way the borders between human and animal, male and female, young and old. Even Tiresia, the seer, and the king Cadmus, in Euripides’s Bacchae, who were already old men, let them be dragged by the divine folly. On the other hand, Dionysus apparitions revealed a manifold divinity: sometimes in the shape of a child, or of a youth or of an adult man, as well as in animal or plant shape. Dionysus’s gaze had the power to induce the manìa (sacred folly) and to compel the one who looked at him to go outside of oneself. As jean-Pierre Vernant as written: “Dionysus teaches us or compels us to become something other with respect of what we are in our ordinary life” (Vernant 1990, p. 103).

[Source: http://library.artstor.org/library/]