A Doppelganger is extremely rare. It is considered to be the evil twin, the harbinger (precursor) of misfortune, the omen of death. In most cases, the victim of this type of haunting is in danger with their immediate surroundings, family, or in some cases the victim themselves are in grave danger of illness or death.
One example of a doppelganger is a dream or illusion that haunted President Abraham Lincoln at time through the winter. On the evening of his election win, looking into a bureau mirror across the room he saw himself full length, but with two faces, on paler than the other. He passes it off as the election excitement and tried to forget about it. However, he couldn't after it showed up again. Lincoln told his wife about it. His wife said it was a sign that he would be elected to a second term, and the paler face meant that he wouldn't live through his second term. Lincoln was assassinated later. Story confirmed by Mary Todd Lincoln, and Private Secretary John Hay.
Poltergeist comes from a German word meaning "noisy spirits". They are commonly blamed or known for violent or detructive activity. They are hard to classify, and no two are really the same.
This type of haunting usually starts with knocks, bankgs, and tapping with no visible cause. Stationary objects, like furniture, will move around by itself. Doors will slam, and lights turn off and on. Pictures may fly off the wall. Beds can shake. It can progress by manifesting through voices and full body apparitions. In extreme cases, fires may break out. Also, scratching or biting can occur. There can be harmful objects being put into ones way as well.
Some people have a theory behind this kind of activity. They say it is caused by a person in the household, known as the "human agent" The agent is usually a teenage girl, who is troubled emotionally. It is believed she manipulates physical objects in the house by psychokinesis (the ability to move things by energy generated in the brain). This is either knowing or unknowingloy done. This energy seems to appear in females around the age of puberty. It seems when it manifests, the girl is in the midst of some emothional or sexual turmoil. The burst of activity comes and goes. Most cases will peak and slowly fade away. While most cases usually involve a teenage girl, it is possible that a teenage boy and older adults can cause it too.
In a lot of poltergeist activity, the case will have nothing to do with ghosts. There will not be a way to help the clients, witnesses, or victim. It is usually best to refer the family to a counselor or mental health care provider.
This type of haunting is not caused by ghosts or humans. Demons are an inhuman entity. They are very intelligent. Fortunately, this type of haunting is really rare.
Demons are pure energy entities. They can be described as an angelic being that will manipulate the person to do something out of the ordinary. They can appear as a black mist, fog, black smoke, or black shadow. They can really take on any form that they wish.
When a demonic possession occurs, the body of the human victim is "taken over". It will be common for a person to display signs of superior intelligence. They may know things they previously did not know. They may speak in "tongues" or a different worldly language they may not have learned. In some cases, the entity can enter and leave the body. This will cause the person to lose all capability of controlling their thoughts, actions, and body movements.
Demonic hauntings start in a subtle way: faucets dripping, scratches in the walls, thumping sounds, and knocking. THey are similar to a poltergeist haunting, only more extreme.
They feed off of your fear. The more you fear it, the stronger they become. Once they create fear they will show their powers. Then they will begin personal attacks. You may hear growling or receive scratches on the skin (usually in lines of three), pushed, shoved, or even hit. The air will become thick and possibley foggy. The temperature will change drastically warmer.
These demons come into our world through a gateway. It usually is a cave, a well, natural hole in the earth, usually no more than ten to twenty feet away from the place of the haunting. People also believes that "ley lines" also act as a magnet or portal for demons or other entities. Another way for them to enter is through a "door". The "door" is usually opened by using an Ouija Board or practicing the form of black magic, witchcraft, or demonic worship.
This type of haunting requires immediate attention. The longer it is allowed to remain, the harder it is to get rid of.
There are several ways to get rid of this type of haunting. You can drive it away on your own. However, you will have to gather the strength within yourself to "command" it to leave. Do not taunt, confront, get angry, and most of all show fear. They may not leave right away, but with persistence and no fear, it iwll eventually go away. If this does not work, you will need to seek assistance from an investigator, a demonologist, or clergy.