What is the Cây Pháo folktale?

See a translation

Haha I will be really frank with you: This is my first time hearing that there's such a thing calls "Cây Pháo folktale", and I have been a native, born-and-raised-in-Vietnam Vietnamese for more than two decade (which means either I should feel ashamed of myself, or the story is just really really obscure. The lack of results even in Vietnamese convinces me that it's more likely to be the latter).

But anyway, here's what Google told me: In ancient time, amongst the monsters that roam the land of Vietnam, there were this husband and wife couple that terrorized Vietnamese. These two liked to lurk in the dark and feared bright light and loud noises. At some point, someone noticed this and thus came up with the brilliant idea of having bright light display and lighting strings of firecrackers during New Year Eve (when all the good Gods came back to Heaven to report to the God King) to chase this couple away. Hence the tradition of lighting firecrackers during New Year Eve in Vietnam.

"Cây Pháo" literally means a tall pillar where they hang the firecrackers to light them up, or a long string of firecrackers.