A great misfortune has befallen those who fell here, and it would be best to leave before it falls again. Leaving before 10 seconds have elapsed should avoid the Luck check. This check is repeated every 10 seconds, and failing one causes that harmless looking skinny dog named Pariah to join the party, over the party limit. Having the dog along reduces Luck to one (or two with the Gifted trait) and adds 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.
Pariah can be killed by luring it onto the electrified floor on level two of the Sierra Army Depot; its finely tuned survival sense only works in the specific context of combat. Extracting its 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.