Siren

Sirens are Monsters that live on an island in the Sea of Monsters. They are part human, and part bird. They can sing a powerful song that can force you to want to get to them, but there are mines, and sharp rocks that will kill you if you try. According to Annabeth, "The Sirens sing the truth about what you desire. They tell you things about yourself you didn't even realize. That's what's so enchanting. If you survive, you are said to become wiser".

Appearance
In the series, the Siren's appeared as human sized vultures, with dirty black plumage, grey talons and wrinkled pink necks. They had human heads that changed to the people you knew, always smiling assuringly, but their mouths were always greasy and caked with the remnants of old meals.

In the mythology, they would first appear as a beautiful naked woman playing a harp.

The Sea of Monsters
After their close escape from Circe's island, Annabeth persuaded Percy to let her hear the Sirens so she would gain more wisdom. Percy had her tied up in rope but she managed to escape, so Percy went after her. When he touched her he saw what she saw. It was her dad and Athena sitting down together. Also there was Luke, no longer evil, sitting down gesturing her to sit next to him. In background, New York was completely redesigned by Annabeth. The buildings were made of white marble with gold windows. From this she learned her fatal flaw: hubris.