P2R-866 was the Tau'ri designation of a planet in the Milky Way galaxy which held a Stargate and was home to a group of Humans. Sometime during the Ori invasion of the Milky Way, the people were visited by a Prior who managed to convert the population to Origin. Sometime after this, they were monitored by an SG team who were using modified Sodan Invisibility devices.
As such, P2R-866 was one of the worlds which were exposed to an Interdimensional parasite that infested the local wildlife and turned them into rabid carnivores. When Stargate Command learned that these creatures were attacking the population, they knew that the Ori were not responsible for the rabid creatures as the entire planet had converted. Whether or not the Tau'ri or the Ori took care of this creature is unknown, but it likely that the Tau'ri would feel some sort of guilt for inflicting it on the people and take care of it. (SG1: "Uninvited")