Probably referring to the 'neuralyzer' gadget from the movie Men In Black (https://en.wikipedia.org/wiki/Neuralyzer https://en.wikipedia.org/wiki/Neuralyzer).

Probably referring to the 'neuralyzer' gadget from the movie Men In Black (https://en.wikipedia.org/wiki/Neuralyzer https://en.wikipedia.org/wiki/Neuralyzer). But could also be a reference to the 'visual knock-out capsules' from Alfred Bester's SF novel 'The Demolished Man': "They were cubes of copper, half the size of fulminating caps, but twice as deadly. When they were broken open, they erupted a dazzling blue flare that ionized the Rhodopsin - the visual purple in the retina of the eye - blinding the victim and abolishing his perception of time and space."