Jubokko is a tree spirit that grows in areas where mass amounts of human blood were spilled on the ground, such as battlefields or execution sites. They sucked up so much of this blood that they turned into demons. These trees, having sucked up humans' blood to be born, will bleed when they're cut. They are sturdier than other trees and heal their wounds quickly. It's said that their branches, if obtained with permission, can be used as powerful healing and cleansing items. They may hide among bushes and trees and can organize themselves to make someone lose their way in a forest, through communication.
He is described in the "Yokai encyclopedia" of the cartoonist Mizuki Shigeru. Kyougoku Natsuhiko, Tada Katsumi and Murakami Kenji (a group of yokai researchers) suspect this is an invention of Mizuki Shigeru since they couldn't find traces of this vampiric plant in folklore records, legends and old literature. They could not find the actual source as Mizuki is secretive about his sources.