1) Demon, Elemental: An Evil Spirit, an Agent of Evil, Harm, Distress or Ruin

2) Ghost: A disembodied soul, especially the soul of a dead person believed to be an inhabitant of the unseen world, or to appear in bodily likeness.

3) Poltergeist : A noisy, mischievous ghost held to be responsible for unexplained noises.

4) Appararition: : An unusual or unexpected sight: Ghostly Figure