Letharia Vulpina
Wolf lichen. Used to poison wolves. It used to be mixed with ground glass. The glass would perforate the digestive tract and allow the poison from the lichen to enter the bloodstream.
[[Dr. Alan Deaton|Deaton]][[Alan Deaton|Deaton]] finds letharia vulpina growing in the shinto temple where the [[nogitsune]] that [[Chris Argent|Chris]] encountered's blood dripped onto a fountain.