Midnight Ranch Attacks

 is an unmarked quest in Fallout: New Vegas.

Something has been killing Brahmin at night in Novac. No-Bark Noonan says he saw an invisible monster doing the killing. Stake out the pens at night and find out who's to blame.

Quick walkthrough
Speaking to No-Bark Noonan in Novac indicates the player should speak to Dusty McBride about Brahmin who are being killed on his ranch. Dusty informs the courier they should wait in his ranch in Novac at midnight. You will see the attacker is a crazed Nightkin. The Nightkin carries a message entitled The screams of brahmin. Upon completing the quest Dusty will inform the player they can have access to his Brahmin Steaks in the freezer. Additionally the courier will gain Reputation with the town and positive Karma. Also for an added bonus, the Nightkin will have a Minigun.

Video walkthrough
You can find a video walkthrough at Gaming Drunk.

Bugs

 * Sometimes the Nightkin will not attack the Brahmin but only stand there cloaked unless he was recently attacked possibly by a Glowing One, if this happens, the Nightkin is in front of the house at night, or during the Day he is found behind a rock next to a broken fence, but if it is killed without seeing it as it is killing the Brahmin, the quest will be un-completable.


 * You can actually complete this quest after you kill the Nightkin as in the above description. When you come here later you will find him alive standing as described lower and after killing him again you will be able to end the quest by talking to the quest giver.


 * Another alternative is to try standing near the Nightkin while it's cloaked during the day (behind a nearby rock) and use the wait function to fast forward until around midnight. After a few moments, it will hopefully pull out its minigun while still invisible, and proceed to attack the Brahmin. (Worked in one case on the Xbox 360)


 * The Nightkin may actually appear visible behind the fence, yet no NPC will react to his presence, even Novac Settlers that would literally brush up against it.


 * Have killed the nightkin but didn't have the mission finish. Might have been because he ran away and went yellow, but either way mission did not finish.


 * CAUTION: If you leave this quest for too long after finding it, the Nightkin may end up killing all the cattle while you're away, or in a different part of the area. It is unknown whether the ranchers will acquire more cattle if they run out.

I had this bug and tried the various bug work arounds and they didn't work. I decided to go back to a save before I talked to anyone for the Boone quest, and particularly No-Bark, who gives to hints for this quest as well. I went straight to the pen after talking to the farmer and then waited using the "wait" function. I was removen from wait be the nightkin shooting a beast. Killed it, looted the body, and went back to teh rancher and was able to finish the quest.

Summary: Either talking to No-Bark about this quest or talkign to the people about the Boone quest may be causing this bug.