Python was a draconic or serpentine creature from Greek mythology. It was created by Gaia to protect the shrine of Delphi, believed by the Greeks to be the centre of the world. When Apollo came to claim the site as his own (though in some cases, it belonged to his ancestress; the Titan Phoebe, or her sisters Themis or Theia), he slew the Python. The myth can be used as an allegory - Apollo (the sun god) uses his arrows (shafts of sunlight) to rid Delphi (the centre of the world) from the Python, representing rot; the Greek verb "πύθειν" means "to rot".
The Pythonidae family of snakes are named after it, as is the title for the presiding prophetess of Apollo at the oracular site; the Pythia.