The night spirit Nishi is considered one of the most terrifying ghosts in Bihar and Bengal, regions in eastern India. It appears only as Nishir Dak (literally “the night call” or “the call from darkness,” from the Bengali নিশি [Nishi] — “night, darkness” and ডাক [Dak] — “call”) — a voice calling a person by name in the middle of the night while they sleep. Following the call, which sounds exactly like the voice of someone familiar, the victim is drawn to a secluded place outside the home, where it exposes its actual form to the helpless victim and nearly always kills the victim. The body of the victim almost all the time disappears leaving no remnants making it hard for the person’s close one to understand the real way of his or her death.

If a person hears the voice of a loved one or acquaintance calling them once or twice during the night, it is believed to be Nishi trying to trick them into answering. By responding to the call, the person allows the spirit to consume their soul. However, if the voice calls a third time, it is considered safe to answer, since Nishi can only call a person by name twice.

Those who know of Nishir Dak avoid going out alone at night, fearing they may become the spirit’s next victim.

Bijoy Chakraborty was returning from his work as night dawned. He moved through the fields at a fast pace, he heard a faint yet clear voice calling him from behind “Biju, where are you going?” (Biju, kothay jacchis) At first, he thought it might be someone he saw in his surroundings but there was no one and yet again he heard the voice a bit louder and the sound was feminine. It again asked, “Biju, where are you going? Come to me” (Biju, kothay jachis, amar kache ay). This time it sounded to the voice that resembled his grandma, who reared him from his childhood and who died a few years back. Bijoy responded to the voice “Grandma where are you” (Didima, tumi kothay?), something by then had changed someone told in his ears that she was there he ran towards that voice and started running in a stage of trance, going after a few kilometers he entered the woods and a layer of mist covered him and he never seen again in spite of the villagers searching every nook and corner.

In some stories, Nishi is the ghost of a deceased mother who loved her child so deeply that even after death she cannot bear to remain without them in the afterlife. She calls to the child at night and leads them to certain death, compelling them to drown themselves or hang themselves.

According to another version, the Nishis are thought to be the spirits of persons who did not have a respectful or complete release or pind-daan as they transitioned from the earth to the astral worlds.

A tea trader from Bihar, and he tells that there is a Nishi who is always on the lookout in and around his area. They also know that the Nishi is the soul of a peasant who died many decades ago but whose family did not complete the ceremonies at Gaya’s Pret Pahar — the Mountain of Spirits.

People murdered in car accidents, particularly on isolated roads at night, are frequently thought to have been killed by Nishis who need to kill to survive. So, it is said, are individuals who die unexpectedly and unexplainably at night. Many people think that unless particular rites are conducted for the soul of a Nishi victim, the victim will also become a Nishi.

Bengalis also use the “call of Nishi” to explain the phenomenon of sleepwalking.