Siren

n. One of several musical prodigies famous for a vain attempt to dissuade Odysseus from a life on the ocean wave. Figuratively, any lady of splendid promise, dissembled purpose and disappointing performance.

That the human-headed bird represents a Siren  in Greek art is amply attested by the representations of Odysseus' adventure with the vocal enchantresses. Their appearance on the so-called Harpy monument of Xanthos, however, shows them in another aspect, that of death-deities—not necessarily of a violent and rapacious character, as on a vase in Berlin, but gentle and kindly. So, again, a Siren is represented in connection with a tomb; and in a scene representing a banquet in Elysium they are depicted crowning the dead. On some vases we find a Siren playing a flute or a lyre (probably merely fanciful subjects); or, again, two Sirens kissing each other. As mere decorative motives their appearances are countless, and many early vases are modelled in the form of Sirens; sometimes they have human arms; in one case a bird's wings and a fish-tail; or, again, more anomalously, bearded masculine heads. More rarely they are seen flying.