The Laser Knife is an item in OverBlood.
The knife is gained in order to cut a grate in the "Hallway with the Bad Noise". It then seems to serve no other purpose.
Raz uses the knife to dispatch the first enemy in the game. In spite of this, the Laser Knife cannot be used as a weapon at any point, and after it is used, it is lost; Raz makes no attempt to remove the knife from the creature's body, and the player is unable to.