Bre'el IV moon

From Memory Alpha, the free Star Trek reference

The Bre'el IV moon was a moon in orbit of Bre'el IV in the Bre'el system.

In 2366, the moon began to fall out of orbit, threatening the planet. Q theorized that this was caused by a large celestial object passing at near right-angles to the plane of the star system, likely a black hole. The USS Enterprise-D made several attempts to return the moon to its proper orbit, but was unable to do so. Disaster was ultimately averted by Q when he returned the moon to its proper placement. (TNG: "Deja Q")