A knock-out ray was a type of weapon used by a race of robots encountered by the crew of the USS Enterprise on stardate 24.09.45. The robots used the knock-out ray to knock the Enterprise crew unconscious, after having demanded then entire crew disembark onto their planet. The effects of the weapon were temporary, allowing the crew woke up unassisted some time later. (TOS comic: "Life Form Nonexistent")
- The exact nature of the knock-out ray is not explained, but seems to have a similar function to the stun setting on a phaser, or stun grenades.