The Beta Renner cloud was an intelligent, spaceborne entity.
The USS Enterprise-D encountered it near the Beta Renner system in 2364. It came aboard the Enterprise and began making efforts to return to its "home". After interfacing with several ship's systems, it entered the neural systems of several crew members, including Jean-Luc Picard, in an attempt to establish contact with others. (TNG: "Lonely Among Us")