A populous star system found utterly dead in The Immunity Syndrome, its billions of inhabitants and the Vulcan-crewed USS Intrepid drained by a vast single-celled organism.
The Gamma 7A system is where the Original Series episode The Immunity Syndrome begins. The Enterprise crew is on its way to a much-needed rest when Starbase 6 reports that all contact with the system and with the starship Intrepid, sent to investigate, has been lost. At the same moment Spock feels the deaths of the Intrepid's four hundred Vulcans.
Long-range scans show that the system's star and its billions of inhabitants are dead. In their place is a zone of darkness that saps energy from machines and living things alike.
Inside lies an immense single-celled creature, thousands of miles long and ready to divide. Spock pilots a shuttlecraft into it to find its weak point, and Kirk destroys it from within using an antimatter charge.