From this month's Mount Skin:
"Mount Cosmetic Skin
On the 31st of Oleidus, the traditional Verran holiday known as Demontide, The Unseen Order conducts an annual ceremony they call The Collection, at the stroke of middle night. Any members of the sect who possess a Collector’s Touch glove gather to conduct a blood-crazed invocation and summoning ritual. A torchlit forest clearing is filled with a cacophony of maniacal, disembodied laughter, and the grinding, rumbling, and snapping of bones. Limbs and body parts from an untold variety of creatures animate and combine, forming the shambling, undead abominations known as Sacrificial Remnants. These large, many-headed beasts drag themselves about on their hands and knees, scraping the ground with their oversized knuckle bones, as they faithfully obey the orders of the cult leaders."
So, the Halloween Event is called "Demontide", and it's in the month of "Oleidus".
"Mount Cosmetic Skin
On the 31st of Oleidus, the traditional Verran holiday known as Demontide, The Unseen Order conducts an annual ceremony they call The Collection, at the stroke of middle night. Any members of the sect who possess a Collector’s Touch glove gather to conduct a blood-crazed invocation and summoning ritual. A torchlit forest clearing is filled with a cacophony of maniacal, disembodied laughter, and the grinding, rumbling, and snapping of bones. Limbs and body parts from an untold variety of creatures animate and combine, forming the shambling, undead abominations known as Sacrificial Remnants. These large, many-headed beasts drag themselves about on their hands and knees, scraping the ground with their oversized knuckle bones, as they faithfully obey the orders of the cult leaders."
So, the Halloween Event is called "Demontide", and it's in the month of "Oleidus".