A great misfortune has befallen those who fell here, and you would do well to leave before it falls upon you. Leave before 10 seconds have elapsed, and you should miss the Luck check. They are repeated every 10 seconds. Fail a check, and that harmless looking skinny dog named Pariah will join your party, over the party limit. It reduces your Luck to one, or two if you have the Gifted trait, and gives you the Jinxed trait.
The requirement for this special encounter is Level 10.
Pariah will use all of its seven AP to run to the nearest exit of any map once combat starts, and it has 750 HP. Once it dies, both the perk and the stat decrease disappear, except in the rare case of it being killed with a zero damage critical.
He can be killed by luring him onto the electrified floor on level two of the Sierra Army Depot; his finely tuned survival sense only works in the specific context of combat. Extracting his brains in the organ extraction chamber on level 3, will yield two brains and -200 Karma.
Like the Masticator in New Reno, Pariah gives a stat decrease that can actually be used exploitatively. Gain Luck and the mutually exclusive Hubologist zeta scans, if they are received before encountering the dog, stop the decrease in Luck. The increase in Luck that would normally occur to restore Luck, when the dog dies, instead adds Luck. NCR's zeta scan gives +2 Luck / -1 Luck, SF's, +1 Luck and +1 Intelligence / -1 Luck, depending on...Luck.