1. Most cults are peaceful and not harmful, but some cults have dangerous characteristics like worshipping a guru over religious teachings, using brainwashing techniques, and abusing members financially or sexually. 2. The Aum Shinrikyo cult in Japan carried out a deadly sarin gas attack on Tokyo subways in 1995 that killed 13 people and injured 50. 3. Several cults throughout history convinced members to commit mass suicide such as Heaven's Gate, Jonestown, and others.