Our ancestor have a firm belief and even my late father told me some instances that a dead body left unattended at night without strict watch and safeguard becomes a target of evil spirits and turns into a Rolong. “Ro” means corpse and “Long” means to rise.
When evil spirit enters the body of the death firstly there is some movement in it, then it starts rising and instantly assumes a terrible form with long-drawn-out tongue, bulging eyes and oozing blood from nostrils, etc. It blows a puff of air from its mouth and all persons falling in its ambit instantly are turned into evil spirits and start dancing with it under its spell.
Then the Rolong comes out of the house dancing and all the persons under its influence follow the suit. On the way whosoever comes into contact they turn into an evil spirit by the mere puff of air from the mouths and he/she too starts following them. The Rolong leads them all to a steep rock where it jumps down from the top of it and all others too follow it. Thus all perished there.
However, this disaster can be averted if the phenomenon of the revival of the corpse is dictated timely, and the dead body is cut into pieces and the pieces are scattered away. For it is said that an evil spirit enters into an undamaged body only.
Moreover, if the dissevered parts of the body are scattered distantly they reassemble and assume a more terrible form of a Rolong than the original. Therefore, the separated parts of the dead body, influenced by the evil spirit, are either scattered distantly or offered to dogs to eat them away. It is on account of this that the person appointed to keep a strict vigil on the corpse at night always keeps an axe with them to meet the consequence if any arises there.
Beside, seeds of mustard, religious books, fire and sun light too are said to be deterrent to the evil effect of evil spirits. It is for this reason that a butter lamp is kept burning beside the corpse round the clock and seeds of mustard and religious book are keep invariably there. Rolong does not enter in the daylight.
At night vigilant watchmen keep sharp eye on the dead body. In case of any suspicion of entering the evil spirit into it, the religious book is kept on the chest of the corpse and Lama is asked to ward off its influence.
Moreover, a Lama, endowed with supernatural powers, if contacted timely can destroy the Rolong and bring back the affected person into sanity.
So this is the very reason why corpse is protected in the night. It will be great benefits if Molem recitations are made in the night.
Hopefully, this is reason of guarding dead body in night.