Naga fireball

[3] The phenomenon is locally attributed to phaya nak, a giant serpent (Nāga) said to live in the Mekong.

[1] The fireballs are most often reported around the night of Wan Ok Phansa at the end of Buddhist Lent in late-October.

[5] Thai biologist Jessada Denduangboripant analysed footage of a Naga fireball event and concluded that the effect was caused by the firing of flare guns from the other side of the river.

[6][7] A 2021 official investigation by Lao authorities during a COVID-19 lockdown and curfew, concluded "In response to the news in foreign media, I would like to state that it is extremely unlikely that anyone could have fired weapons or flare ammunition without our knowledge on that night.

One explanation is that the fireball is a result of flammable phosphine gas generated by the marshy environment.

The tracks of two Naga fireballs (at left) rising vertically into the sky before petering out near the top of the photo. The other tracks are of sky lanterns or fireworks.