Babi Ngepet is a boar or swine demon in Javanese mythology. According to local myth, the creature is believed to be the manifestation of a person practising black magic. It is a kind of magic to help people become rich instantly, but in exchange they must sacrifice their humanity, allow themselves to be transformed into a boar. The human-animal transformation is similar to shapeshifting or the werewolf concept in the West.
The myth told about a man enveloped in black robes before miraculously turning into this creature. After the transformation, the boar demon roams around the village, scratching its body against the wall, door, cupboard, or furniture. Magically the belongings of the villagers, such as money, gold, and jewellery will disappear and magically carried away by Babi Ngepet. If the mission was successful, when Babi Ngepet safely returns home and transforms back into human form, the black robes will be filled with the stolen money or jewellery.
The person that practices Babi Ngepet black magic needs assistance from another person. The assistant's task is to stay home and guard the lit candle floating on a basin of water, while Babi Ngepet is in action. If the fire on the candle is shaking, fading or almost out, it is the sign that Babi Ngepet is in danger. Another myth said, the person that practices Babi Ngepet black magic will be trapped forever in his demonic boar form if the fire on the candle is completely out.