The Phaya Naga or Naga are serpent-like creatures believed by locals to live in the Laotian stretch of the Mekong river or estuaries, also northeastern people of Thailand. People in both Laos and Thailand attribute the Naga fireballs to these creatures, which are likely to be extremely overgrown giant mottled eels (Anguilla marmorata), an undiscovered species of eel or just methane.

Lao myth maintains that the Naga are the protectors of Vientiane, and by extension, the Lao state. The Naga association was most clearly articulated during and immediately after the reign of Anouvong. Leup Phasun, an important poem from this period discusses relations between Laos and Siam in a veiled manner, using the Naga and the Garuda, to represent Laos and Siam, respectively.