The Ekina, tractored into DS9.
The Ekina was a "cargo ship", caught in a plasma storm near Deep Space 9 in 2370. It sent a distress call to the station, stating that their engines had been severely damaged, and would, subsequently, be tractored into the station's outer docking ring. In reality, however, the Ekina was a ship used by Verad, to hijack Deep Space 9, in order to steal the Dax symbiont from Jadzia Dax. (DS9: "Invasive Procedures")
For more information on this studio model, see Studio models (TNG).