Winter Worm

is a Quest related item necessary for obtaining a Formation Manual.
==Obtainment==
Acquired by interacting with the (Wormwrought Valley) during the Winter SeasonSettings\MapStories\MapStory_Special.xml, as well as by purchasing from Sects or the Merchant. 
==Uses==
Visiting Celestial Pool while having both Summer Herb and Winter Worm buffs active drops the Formation Manual "Polarized Diagrams of Mt. Zhongyuan".
==References==