Neural Implant.
First Appearance: "Into the Moonless Night."
Details: After Lexa Pierce attempted to leave the GSA, Mason Eckhart set up Project Nine, an operation during which four Genomex scientists placed a neural implant placed in her neck which gave him complete control over her nervous system and her actions by inducing a REM sleep-like trance. The Dominion doctors temporarily deactivated the implant, but it was reactivated by Project Nine scientist Dr. John Gonsalves several years later. Any attempt to remove the device would trigger an electrical surge into her brain, causing an instant hemorrhage, but once Jesse Kilmartin determined that the trance could be broken with epinephrine, he and Adam Kane successfully removed the implant.