Project Retiarius
From Absit Omen Lexicon
Project Retiarius is the working code name for a Department of Mysteries endeavor to create a net that will hold a Dementor for the purpose of capture, control, and transportation.
As of summer 2010, the net appears to be a lattice of silvery, shimmering silver fibers. It reminds one of the color of a Patronus.
This project is classified, although the Daily Prophet reported on such an artefact at the Dementor Attack Hollywell Copse on April 23rd.
It was tested on a captive Dementor on June 11 following the Dementor Attack Nottinghamshire Funeral. [1]