Wraith probe
From The Stargate Omnipedia
Scouting device of Wraith origin, slightly larger than a beach ball, which can be dispatched through Stargates in search of technology which may link to the Ancients. It is not known if the probe's purpose is also to determine the size and worth of suitable feeding grounds for the Wraith, though this is likely.
KEY EPISODE
Childhood's End - The inhabitants, who fear they have let their guard down with the Full-Growns, encounter a Wraith probe, which scans the Puddle Jumper.