ectometer
A device designed to detect ghosts.
This handheld ectoplasmic scanning device was developed to detect spirit activity within an area. It has a location map to pinpoint a spirit's location and an ectometer to determine density of trace matter and spirit strength
Where it comes from
From ecto- + -meter; likely coined to describe the "psychokinetic energy detector" from the 1984 movie Ghostbusters.
Adapted from the Wiktionary entry ectometer (CC BY-SA 4.0).