A Devil's Triangle consists of three bags of magnetic particles called "flecks" placed at three points. This causes massive disruption in the magnetic particles that a bird uses for navigation, which results in disorientation and confusion. Any bird unlucky enough to come into the magnetic field created within the triangle of the three bags experienced these effects, including owls.
One victim of a triangle, Ezylryb, found that when he entered the Triangle, none of the stars lined up properly and that when he thought he was going east, he was actually going west.
The Pure Ones (Books) used these Triangles extensively, finding them to be an effective weapon. They first tried them in a successful to capture Ezylryb, but the triangle was destroyed when the Chaw of Chaws came to his rescue. The Chaw of Chaws targeted the bags of flecks and destroyed them with fire, the flecks' only weakness.
Later on, the Pure Ones set up extensive emplacements of the Devil's Triangles around their encampment in the St. Aeogolius Canyons, especially around the area called the Great Horns. The triangles were destroyed by Bubo and Soren, who went on an undercover mission before the Battle of the Burning to do so.