During the Battle of Chin'toka, a Dominion War battle that occurred in the episode "The Changing Face of Evil", the Breen employ an energy-damping weapon that could shut down all systems on Alliance ships. The Klingons subsequently discover an engine modification that renders Klingon ships immune to this weapon, though it does not work on Federation or Romulan ships since they are powered differently. The Breen used this weapon to great effect, completely immobilising the USS Defiant, and a fleet of alliance ships, allowing the Breen to destroy them at their leisure.