Sergeant Reznik (Maria Bello) was a villainess from the 2016 film, The 5th Wave.
Reznik was the drill sergeant in charge of training the camp's new recruits, and she was first shown doing so with Zombie, who she later orders to kill one of "The Others," a group of extraterrestrials invading Earth. Later in the film, it is revealed that Reznik, along with the rest of the army, is one of The Others; a silencer sent as part of the 4th Wave.
After learning this, Cassie (the film's protagonist) posed as a recruit to get close to Reznik, and during the screening, Cassie fights the evil Reznik and strangles her to death with the cord of a computer mouse. She then uses her legs to push off of a wall and flings Reznik face-first against the glass window, which seems to break her neck. We lastly see Reznik lying motionless on the floor and her red lipstick smeared on the glass where her head was crushed.