Search and Mark/Fallout: New Vegas

Search and Mark is a companion perk in Fallout: New Vegas.

Effects
When Rex is in your party, food, chems, firearms, and ammunition within a short distance in are highlighted in a green outline while aiming down sights. Containers (i.e. refrigerator, metal box, etc.) that have one or more of these items inside will also be highlighted. Once the items are removed, the container will no longer be highlighted.

Bugs

 * Some killed creatures such as lakelurks will be highlighted despite their bodies not containing anything the player can pick up. In the case of lakelurks this may be due to the lakelurk shriek "weapon" they carry, which is classified as a real weapon with ammunition but cannot be obtained by the player.

Behind the scenes
The name of this perk may be a reference to how hunting dogs search for prey and then "mark" the location by pointing at it.