In 1997, SG-1 visited P3X-562. While there, Colonel Jack O'Neill touched a Unity crystal which rendered him unconscious. In fear of retaliation, the crystal took O'Neill's form in hopes of fixing his pain. The greatest pain it found was not from the physical injury, but the emotional pain from his son's death.
Not understanding the Human concept of death, the crystal O'Neill went to Earth looking for Charlie to bring him back to the real O'Neill. Upon finding a picture of O'Neill with his wife, and son, it decided to continue its search with Sara. Later that day, it started breaking down due to the Earth's electromagnetic field being stronger than P3X-562's, resulting in electrical discharges and radiation. SG-1 tracked it down at a hospital, where Sara had taken it. It told O'Neill that it finally understood what death meant and that it couldn't bring Charlie back to him. Instead, it was able to show O'Neill what of Charlie still existed in him by taking Charlie's form and Jack took it back to P3X-562. (SG1: "Cold Lazarus")