Hmwat? It's rather logical. All poison does is slowing down the attacked unit slightly and causes the attacked unit to lose hp per second. If you rename "Poison" to "Bleeding". It works just the same, because poison and blood loss in this context is the same. The buff could thus be applied to envenomed weapons and then attached to a feral animal, like a wolf or a bear, for example. Poison only works on organic units however, not mechanical ones. Thus, a tank will not encounter the bug of bleeding, because it's very type will be immune. Instead of a green cloud, you now have a blood sfx attached instead.
Thus, the wolf bites you, you start to bleed. You lose more HP. After a while after not being attacked, it goes away. Just like poison. Is it really that difficult for you to understand what I mean?