Agent

Agent n: this can have one of three meanings when pertaining to parapsychology.

1).  The agent is the person who tries to communicate or impart information to another via telepathy or some similar means. Similarly the word describes the person communicating information in an ESP experiment.

2).  The agent is the subject of investigation in a psychokinesis experiment.

3).  The agent is the person who is the focus or at the center of poltergeist activity.