Kukulkan ("Plumed Serpent", "Feathered Serpent") is the name of a Mesoamerican serpent deity. Although heavily Mexicanised, Kukulkan has his origins among the Maya of the Classic Period, when he was known as Waxaklahun Ubah Kan, the War Serpent, and he has been identified as the Postclassic version of the Vision Serpent of Classic Maya art. Sizeable temples to Kukulkan are found at archaeological sites throughout the north of the Yucatán Peninsula, such as Chichen Itza, Uxmal and Mayapan.

Stories are still told about Kukulkan among the modern Yucatec Maya. In one tale, Kukulkan is a boy who was born as a snake. As he grew older it became obvious that he was the plumed serpent and his sister cared for him in a cave. He grew to such a size that his sister was unable to continue feeding him, so he flew out of his cave and into the sea, causing an earthquake. To let his sister know that he is still alive, Kukulkan causes earth tremors every year in July.

More Info: en.wikipedia.org