Vygoire is a remote world in/within range of the Koprulu sector. Some, if not all of the planet is covered in jungle, with the occasional clearing or river bend mudflat. It has an atmosphere that is breathable to terrans.
Vygoire has Permian-level flora and fauna in the form of ferns and insects respectively. It is bereft of more advanced native lifeforms. The planet has two moons that due to different rates of orbit, come into alignment once every 23 days.
At some point prior to the Second Great War, the planet was discovered and overrun by the zerg. Two years after their landfall, the zerg were cleared out. Even a year after that, the signs of old battles could still be found. At some point, the Terran Dominion established a lab complex on the planet to study the after-effects of creep on a planetary ecosystem. It was during this period that the scientists discovered and became infected by psychoactive spores found in the planet's ecosystem.
Three years after the zerg's landfall, contact with the complex was lost. Torch Seven was assigned to investigate. They found the lab abandoned, but with strange graffiti making the walls. The squad went into the jungle to investigate further, but encountered an ultralisk that ambushed them. It wiped out a third of Torch Seven before they managed to escape it.
Later, the squad encountered the scientists, who were crazed due to the psychoactive spores. Doctor Vera Langridge was also among them, but immune to the spore's effects. She told them they were all infected by the same spores. The group went to the scientists village, where they met Gerhardt van Rijn, the former head scientist of the facility, who now was the head priest of the cult of the Great One, who was the ultralisk they had found earlier which had also been inflected by the spores. Just then, the ultralisk came out of the brush, and the cultists began rushing up to be killed by it.
Doakes and Torch Seven went back to the lab, where they made a vespene bomb. They planned lure the ultralisk to a ravine and collapse the rocks on top of him. Doakes distracted the ultralisk while this happened. The plan successfully knocked the ultralisk down, but it arose from the rubble and chased the squad. Doakes got off a lucky shot, which wounded the ultralisk, but he began to succumb to its psychoactive effects.