A downed supply ship
Wraith supply ships are vessels which carry cocooned humans to other parts of the Wraith fleet. They are usually used when the Wraith are in a long battle, and need to be resupplied with humans to feed upon. The Atlantis expedition discovered a crashed supply ship on the Light Bugs' Planet in the Lantean system, one which was intended to feed the Wraith battling the Lanteans who were defending Atlantis. None like it have been seen since, possibly indicating that the vessel type has been discontinued. (SGA: "The Defiant One")
The vessel isn't a class of its own, but is in fact a modified Wraith cruiser, as stated by Lt. Col. John Sheppard. (SGA: "Critical Mass")
| Cruiser · Dart · Escape pod · Hive ship · Scout ship · Supply ship | |