Meta

Meta was a shape shifting being who lived during the 24th century who was similar to the Changeling Odo. A serial killer who worked as an assassin, Meta was responsible for several deaths on Deep Space Nine in 2369.

Meta was brought to Deep Space Nine by the Ferengi Glav in order to kill Quark, who had once cheated Glav in earlier business dealings. To disguise this fact, Meta carried out several murders on Deep Space Nine, intending to kill a few people, kill Quark, and then kill a few more people.

Odo eventually figured out what was going on, and disguised himself as Quark in order to confront Meta. After Meta murdered Glav, Odo pursued Meta throughout Deep Space Nine. Meta tried to escape on a ruanabout, Odo followed him on board. The runabout was destroyed by a nearby Cardassian vessel. Odo and Meta survived the destruction and fought outside the station and drifted through space towards the Bajoran wormhole, which was undergoing violent subspace compression, destroying anything that entered. Meta was drawn into the wormhole and destroyed, however the station's crew was able to beam Odo away before he was drawn into the wormhole.

It has never been revealed whether Meta was an insane Founder, a member of the Hundred, a member of another link spawned by the Progenitor, or something else entirely. Meta may have had knowledge of the Founders, as he made an offer to Odo to tell Odo about his race. (DS9 novel: The Siege)