A spy-fly was a mechnical insect designed to spy on someone and then return with information. They had clockwork mechanisms worked by evil spirits. The spy-fly would not stop as long as the spirit is inside, and upon release, the spirit would kill the first person it could.[1]


Spy-flies could be found in Morocco. John Faa once saw one there.[1]

Marisa Coulter sent two spy-flies to locate Lyra Belacqua after she ran away from her home.[1] Farder Coram managed to capture one and Lyra kept it in a box, later using it to trick Mrs Coulter.



  1. 1.0 1.1 1.2 Northern Lights, Chapter 9