The Extraterrestrial Device, also known as the Extraterrestrial Detector or the P.K.E. Meter, is a device in Grand Theft Auto V. It plays a minor part in some Strangers and Freaks side missions.
The Extraterrestrial Device is a small handheld meter with a handle and a t-shaped antenna at the top. It has a small monitor and two sensor wings protruding from each side, which both move up and down together. In addition, it has various other dials and lights at its front. The device is used to track the location and direction of extraterrestrial beings in relation to the person holding it. It is implied that it utilizes some sort of radar technology, although the exact technology that it uses is largely unknown.
The device is very similar to the P.K.E. Meter, a device used in the Ghostbusters film franchise to detect ghosts and paranormal entities.
The device is used in the Strangers and Freaks mission Far Out by Omega, in which he can be seen walking around the desert next to his trailer with the meter in his hand. When approached by Franklin, he is alarmed and points the meter at him, until it shows a normal reading (and proves that Franklin is, in fact, a human life form.)
The device is seen again in the mission Chasing the Truth for the Epsilon Cult. In this mission, Marnie Allen gives Michael the device and tells him that it can find extraterrestrial beings and objects. He then proceeds to roam the area, finding various commonplace objects which the device indicates are of alien origin. Whenever he finds an object, he asks Marnie if it is the object they are looking for, to which she responds that he must know on his own that it is the one he's meant to locate. Finally, Michael finds an old boot, and claims that he is absolutely sure that this is the object they are looking for, which ends the search. This is the only instance in which the meter can actually be held and used by the player in the game. Ron Jakowski can sometimes be seen standing outside Trevor's trailer with an extraterrestrial device in his hand. These are the only three occasions in which the meter makes appearances in the game.