A system in the Romulan Neutral Zone where an anomaly created in the future threatened to prevent life from developing on Earth.
The Devron system lies in the Romulan Neutral Zone. An anomaly that defies causality forms there, and Picard encounters it in three periods of his life while Q tests humanity.
In All Good Things... and All Good Things..., Part II, Picard finds that the anomaly is caused by the inverse tachyon beams he ordered fired from the Enterprise in three eras. The anomaly spreads backward in time and threatens to prevent life on Earth from forming. Picard has the three Enterprises collapse it.