Most paranormal investigator believe that a poltergeist is not a demon. Although they might move things around in your home or make some kind of physical contact with you it is a very rare case that the living are physically harmed by them. Emotionally harmed for sure and as such they can be quite frightening.
They are often thought of as a negative spirit attracted to a young person, most often a teenager. Due to hormonal and emotional changes in the teenager's body, it is thought that negative energy may be thrust outwardly reportedly moving or destroying objects at times.
There is still much discussion and debate by researchers that investigate these types of paranormal activities as to what really is the case when this sort of activity takes place.
For those who believe in ghosts and spirits it is generally accepted that poltergeist is a nasty spirit, a spirit that is most often found in a haunted house or building. In German, poltern means to knock and geist means spirit.
A poltergeist is said to sometimes center around one specific person in a household. This person is often one who is suffering from some form of emotional turmoil or change in their life so it makes sense that a teen in often involved. Paranormal activity that centers around poltergeist can be mischievous, destructive, malicious, simple teasing, or even spiteful.
Many paranormal researchers and ghost hunters believe that disruptions in the lives of the living caused by a poltergeist are actually the emotional activity that is focused by the people living in that location. Many strongly believe that it has nothing to do with ghosts or activity from the spirit world at all.
A poltergeist is generally not considered to be able to manifest objects from the spirit realm. They seem to only deal with the objects already within and around its physical location, usually the household or in rarer cases, a small community. In the extremely rare cases of actual human possession by a spirit the sudden appearance of objects never seen before is not that uncommon.
Spirits will often try getting your attention by speaking to you, tapping you on the shoulder, tugging at your clothes, poking you, and in very rare cases they may be able to manifest enough energy to throw something or cause an object to move. This sort of paranormal activity does not necessarily mean that someone has an evil spirit on their hands.
Spirits in some types of hauntings often acknowledge the existence of the humans or may try to communicate with them in different kinds of ways, but more often than not they seem to want to be left alone and go about their own business. Certain spirits are sometimes able to move lighter objects with intentions on getting a humans attention, and this is often taken the wrong way and that person is left extremely frightened.
Most people who believe in ghosts feel that spirits are just human personalities, or souls, and if that person was a kind and caring person in life, their spirit will most likely be after death. The same goes for someone who live an angry and cruel life. They seem to keep the same qualities after death as well, and the general consensus around the paranormal community seems to be that activity caused by that which is defined as a poltergeist is caused by these sorts of angry souls.