Behind the scenes
Noctocyanin is an item that appears in Metal Gear Solid V: The Phantom Pain. It debuted in the Gamescom 2015 Mother Base/FOB demo, specifically during the FOB portion of the demo. The game will have the player sense enemies and organisms even if they hadn't actually marked them beforehand when using it.
Special medicinal plant blend that heightens awareness. For a limited time, makes user of nearby organisms without having marked them.
Use: [R3 stick]"
- ―Noctocyanin menu description in the Metal Gear Solid V: The Phantom Pain Gamescom 2015 Mother Base/FOB demo