A Romulan officer made invisible and intangible by the same accident that phases Geordi La Forge and Ro Laren in 2368, who hunts them through the Enterprise-D.
Parem is a Romulan who appears in the episode The Next Phase, played by Brian Cousins.
He serves on a Romulan science ship that has been crippled while testing a cloaking device based on phase inversion. The accident that leaves La Forge and Ro out of phase with normal matter does the same to him. He follows the pair back to the Enterprise, unseen by the crew.
Parem learns that Ro has discovered what happened and holds her at disruptor point, meaning to stop them warning anyone. La Forge charges at him and the two struggle. Parem is pushed through the hull, which is no barrier to a phased body, and drifts off into space. His weapon is left behind and later helps the two officers make themselves noticed.