A plasma wake was the trail of ionized nebular gases left behind by powerful warp engines of starships traveling inside a nebula. The Jem'Hadar were able to detect the cloaked USS Defiant while it traveled through the Badlands in 2373 by homing in on its plasma wake. Jadzia Dax compared it to a Ligorian mastodon moving through the forest – "you may not be able to see it, but it definitely makes the leaves rustle." (DS9: "Blaze of Glory")