Naga Fireballs or Bang Fai Payanak (บั้งไฟพญานาค) observed at various points on the Mekong River around the town of Nong Khai. The reddish fireballs from the size of an egg to the size of a basketball, appear to rise from the bottom of the river and then fly into the sky. No clear explanation for this phenomenon has been offered. Theories put forward include spontaneous ignition of gases on the riverbed,The locals firmly believe that the fireballs come from a mythical serpent living in the river, known as the Naga or Payanak