Black Tar is an ingredient on the Shivering Isles and are produced from the Mushroom Tree. A Mushroom Tree (Dementia) is a dull plant with a russet-colored star shape on an eggshell-colored cap. Black Tar is a powerful ingredient for poisoners as it has only negative effects. In the youth of the mushroom, the tar must be harvested directly from the plant. In maturity, however, the black tar oozes from the tree in rope-like vines. Black Tar can be harvested from multiple vines originating from the same Mushroom Tree. Despite its negative effects, a select few denizens of the isles appear to consume Black Tar as food.