Magnet guns are a type of powerful handheld electromagnetic device that are capable (among other feats) of ripping the fillings out of a man's mouth from a hundred feet.
In "Dipper and Mabel vs. the Future," Dipper and Ford return to the saucer, and use the magnet guns to traverse the spacecraft in search of an adhesive to seal the interdimensional rift's glass casing. Ford's gun seems to work as it is intended to, but Dipper's gun appears to be far less reliable, with the gun undergoing brief malfunctions that renders it unable to latch onto objects without a short delay. After Ford is captured by the saucer's security system, Dipper decides to use the magnet gun to latch onto the pod in an attempt to save his uncle. Though it suffers a short delay, the gun latches onto the pod just as it takes off. After a brief flight over Gravity Falls, Dipper activates the gun's "magnet pulse" capabilities, which successfully brings down the pod.
The guns are round and dark gray. They have scratches on them, accentuating their old appearance. The guns have a strip of blue lights running down their side and the opening has two bars coming out of it.