Spotter

Spotter is a perk in Fallout: New Vegas given to the Courier while they have Craig Boone as their companion.

Effects
This perk will highlight all hostile enemies in red while the player character is "actively aiming". This means using iron-sights or a scope. Enemies will glow green instead of red when using a night-vision scope. This makes enemies easier to spot and attack, especially at long distances or at night. This perk does not, however, highlight cloaked enemies, such as nightkin.