Experimental device created by the Romulans in 2368 that combined a molecular phase inverter with a cloaking device. Matter exposed to the generator would partially exist on another spatial plane. This would render the matter undetectable and enable it to pass through normal matter. The Klingons abandoned research into such a device after several experimental accidents in the 2360s.
A Romulan test of a generator damaged the warp core of the test vehicle. The U.S.S. Enterprise NCC-1701-D responded to the Romulan distress call and assisted in ejecting the warp core and repairing the ship. In the process, the Enterprise was contaminated by chroniton particles, and a transporter malfunction caused the apparent deaths of Chief Engineer La Forge and Ensign Ro. In reality, La Forge and Ro had been phased by the generator. While cleaning up the chroniton contamination, Lieutenant Commander Data ascertained what had happened to La Forge and Ro and was able to return them to normal space.