A false Sha Ka Ree
Sha Ka Ree was an idyllic place in Vulcan mythology, analogous to the Human "Eden" or the Klingon "Qui'Tu" or the Romulan "Vorta Vor", that Spock's half-brother, Sybok, believed he located on a planet at the center of the galaxy. Sybok believed that a powerful entity existed there, which he called "God", and that all life had originated on Sha Ka Ree. Sybok searched for this planet for many years, collecting a group of loyal fundamentalists as he continued to search.
Eventually, Sybok and his followers stole the USS Enterprise-A and used it to travel to where he believed Sha Ka Ree to be. However, he discovered that the entity which he had sought for much of his life was a malevolent being, its only intention to travel beyond the Great Barrier and escape Sha Ka Ree. Sybok was killed by the entity as he held it off to allow Kirk to escape from it. After his death the being cornered Kirk, but was destroyed by a Klingon Bird of Prey that had been pursuing the Enterprise. (Star Trek V: The Final Frontier)