This is an interesting documentary on the duppies, sometimes called jumbies, of Jamaica. The word duppy is believed to come from the Ghana word "adope", meaning dwarf. The Ghana people believed that all spirits appear as dwarves even if they were normal-sized when alive.
The word duppy is a catch-all name used to describe any supernatural spirit or entity. In reality, there are different types of duppies.
The duppy is what some would describe as an earthbound spirit. It's a spirit that is not at rest. A duppy can be male or female and of any racial background. However, in reality the duppies that are encountered are usually either the spirits of native Taino Indians, the spirits of black slaves, or the spirits of white slave owners or their family. The number one most encountered duppy appears to be the spirits of black slaves, followed by Taino Indians and then of white people. Very rarely do people report encounters with spirits from other racial backgrounds, such as Asian.
The European influence on the belief in duppies is quite evident. Duppies that were white women in life are sometimes called higues or old higues, which is a Jamaican derivation of hag. The European word hag, as synonym for witch, comes from the Anglo-Saxon word "hagtessa". These are the types of duppies that like to attack sleeping victims and sit on their chest, paralyzing them and preventing them from breathing. They steal your soul or life-force and if they aren't dealt with then the victim will slowly weaken, sicken and die with time. A minority of duppies are said to actually drink blood, which would put them closer to our notion of a vampire.
Duppies are well known for the ability to shape-shift. They love to appear as black men wearing fancy clothing, complete with top hat. Two of their other favorite forms are that of a headless person and or of an animal. When appearing in animal form there is usually something wrong with them or something not quite right. This is how people are able to tell that they are duppies in disguise. For example, those that appear as horses may have only three legs. They may appear as albino animals or as a dark version of a normally light colored animal. They may have strangely colored eyes or eyes that glow red. In the documentary, a woman briefly recounts her experience with a duppy in the form of a calf with chains wrapped around it. This is a notorious duppy whom Jamaicans call "rolling calf".
Pay attention to the remedies given for how to protect yourself from and deal with duppies. These can be used against most negative spirits. One of the ways to protect yourself from a duppy that is trying to follow you is to turn your hat backwards. Turning your hat backwards or clothing inside-out is a common European derived practiced that is used as protection against fairies and other negative spirits. It is believed that turning your hat backwards, clothing inside out, and/or putting shoes on the wrong feet, confuses the spirits so that they can not harm you. The recitation of Psalms and of course the speaking of Christ's name is also used.
I like the documentary. However, I do think the creator should have included more info on Obeah in it. There is some info in the latter half though. Obeah is the local magical practice of Jamaica. It is very similar to hoodoo in that it is not an actual religion such as the many ATR's, but is a system of folk magic, folk medicine, and folklore. However, Obeah is against the law in Jamaica so maybe that is why he didn't include a lot about it.