Bob the Wraith
Only name given to a Wraith commander who infiltrated the city of Atlantis via a Wraith Dart's evacuating culling beam. Bob spent approximately two weeks hiding in the city. Though his exact intentions are unknown, he probed Teyla Emmagan's dreams while she slept (or she received nightmares simply by virtue of his proximity).
When the biometric sensor array was calibrated for Wraith life signs Bob's presence was discovered. He shot Major John Sheppard with a stunner rifle and attempted to feed, but he was disabled by Lieutenant Aiden Ford. Bob was taken to a holding cell where he refused to divulge any information. After attempting to probe Teyla's mind, Sheppard shot him to the point where he could not recover from his injuries.
The Gift - Teyla has visions of Bob (not to mention herself as a Wraith) in her sleep.
The Siege, Part 1 - Bob is captured by Sheppard's military unit but will not give up any previously undisclosed information regarding the plans of his people.