Nang Tani is actually one of the female spirits of Thai folklore. According to folk tradition, this ghost appears as a young woman that haunts wild banana trees known in the Thai language as Kluai Tani. Nang Tani belongs to a type of female ghosts or fairies related to trees known generically as Nang Mai in Thai lore. There is a similar spirit in Cambodian folklore, as well as in the Lao popular tradition. Other than that, Nang Tani may also be called Phi Tani.
Nang Tani appears as a beautiful young woman with long black hair, crimson red lips, and a greenish complexion. The outfit they wear may differ from other sources, but they are commonly seen wearing traditional green Thai clothing. Appears in a standing position where her feet never touch the ground or her legs are not visible to anyone.
Nang Tani lives in wild banana trees. She is known to be a gentle spirit and she sometimes even offers food to monks during their morning alms. According to the legends, although she will only reveal her form during a full moon, Nang Tani will come out and punish bad men who have wronged women if given the chance. Her banana tree can be found in rural villages. Her fruits will be inedible. Nang Tani is capable of levitation and flight to a certain degree.
Locals avoid cutting down her tree, as it will definitely bring bad luck and also probably a late-night visit from an angry one. There are actually many inhabitants who make offerings to her in the form of incense sticks, flowers, and sweets. It is believed that banana trees that are wrapped in colorful clothes are haunted by the Nang Tani. Because of the existence of Nang Tani, it is actually considered not recommended to have wild banana trees near your house.
Sources: YouTube Mythology Unleashed.