What is "polong"

Polong is Malay for a spirit enslaved by a man (most of the time) for personal use. Like the Hantu Raya and Toyol, it has a master. It is an unseen ghost that can be used by a black magic practitioner to harm someone. It is particularly meant to harm other people, especially when the owner has wicked intentions towards these people.

Polong is one of the ghosts mentioned in "Hikayat Abdullah", written by Abdullah bin Abdul Kadir, much to the amusement of Sir Thomas Stamford Bingley Raffles, his employer.