Probably the ugliest living thing in Wildwood, resembling something taken from the cat's litter box and stuck on a stick. It can be several inches long, rough, woody, blackened, wrapping around the branch or twig of cherry, plum or apricot trees (genus Prunus). It is a parasite, living off the tree's living tissues, eventually killing the branch, and sometimes the entire tree. Technically the black knot is not the fungus, but contains the fungus; it is mostly made of plant cells that have been triggered to multiply without control by chemicals secreted by the fungus. In other words, it is a plant tumor. In wet weather, usually in the spring, spores are produced from the knot and spread to other plants.

A serious pest of orchards and a bane of those who plant ornamental cherries. In Wildwood it is occasional on cherry trees.

Unmistakeable, unless you come across the work of a prankster sticking dung in the trees.