Considered an Earth Goddess in most literature, she was a witness of Buddha’s enlightenment.
At one point, according to traditional versions of the Buddha's life, the evil Mara sent his three daughters to seduce Buddha and then his army to stop Buddha from attaining enlightenment. The Buddha touched the ground and Mae Thorani, a Goddess of the Earth appeared. She wrung the water from her hair (representing the good merit accumulated by Buddha in his previous lives) and this caused a flood that swept away Mara's daughters & army.
In the Wat Lao in the US, there are a variety of styles to appreciate- almost no two are alike as you can see in the following examples: