Stalking is defined as the willful and repeated following, watching, and/or harassing of another person, sometimes done out of obsession or derangement. In most cases, the purpose of stalking is to force a relationship with an unwilling or unavailable target. The act of stalking is a continuous process, consisting of numerous incidents. Stalking is a form of mental assault, in which the perpetrator repeatedly, unwantedly, and disruptively breaks into the life-world of the victim, with whom they have no relationship (or no longer have). For the most part, the separate acts that make up the intrusion cannot by themselves cause the mental abuse, but taken together they do, as there is a cumulative effect. Contrary to other crimes that usually consist of a single act, stalking consists of a series of actions, which in themselves can be legal, such as calling on the phone or sending emails. Most stalking cases do not rise to extreme levels of violence or harassment.