The Anal Probe is a 50-foot satellite that aliens implant in the rectums of assorted targets. First reference to the Anal Probe Satellite, is in "Cartman Gets an Anal Probe", in which Cartman suffers repeated alien abduction from the Visitors, who implant the device. However, the device apparently suffers from technical problems, as it occasionally shoots fire out of Cartman's ass. It could also be used to control the victim, resulting in Cartman singing "I wanna singa" with rosy cheeks on repeat occasions. Later, when the boys attempt to summon the Visitors, to get back Kyle's brother Ike, the probe extends into the fully-sized dish, summoning the Visitors back.
Although it is initially believed that the device was removed from Cartman after the incident was over, it was later revealed the device was still hiding in Cartman's ass, and operational. However, in "Cancelled", when the device began to suffer from malfunctions again, Cartman was again abducted. However, this led to a repeat of past events involving the Visitors. The boys, along with Chef attempt to escape the Visitors, but the boys are later separated from Chef, where they discover the probe/satellite is used to broadcast TV signals into space, because Earth is in truth an intergalactic reality TV show. When the human race discovers this fact, it results in the show almost being cancelled. However, the boys convince/blackmail the executives to simply mind-wipe all of Earth's memories of being a TV show, and return life to normal. Cartman to this day, still has a probe/satellite in his ass.