An addictive headset game that stimulates the brain's pleasure centres and leaves players open to suggestion, used in a Ktarian plot to take over the Enterprise-D in The Game.
The Ktarian game is worn like a pair of spectacles and projects a simple puzzle of discs and funnels directly into the player's vision. Each success is rewarded with a jolt of pleasure, and repeated play erodes the capacity for reasoning, making the player obedient.
In the Next Generation episode The Game, Riker is given the device on Risa by a Ktarian woman, Etana Jol, and brings it back to the ship. It spreads quickly through the crew, who press it on anyone who has not yet tried it, and Crusher deactivates Data because he would be immune.
The visiting cadet Wesley Crusher and Ensign Robin Lefler see what is happening and work to resist. Wesley holds out long enough to reactivate Data, who frees the crew with flashes of light before the ship can be handed over to the Ktarians.