Warship of Commander Sunad of Zalkon, sent to capture the evolving fugitive known as John Doe in Transfigurations.
The Zalkonian warship was the vessel of Commander Sunad of the planet Zalkon. In Transfigurations it intercepted the Enterprise-D, which had rescued a critically injured man from a crashed escape pod and nicknamed him John Doe while he recovered without his memory.
Sunad claimed John was a dangerous criminal facing execution, but Picard refused to hand him over. The truth was that John was one of a number of Zalkonians undergoing a transformation into a being of pure energy, something their government feared. When Sunad came aboard to take him, John completed his change and left the Enterprise to explore space as a being of energy.