Creatures that either mimic or are a type of plant (including fungi). Ancient societies often had complex beliefs and rituals regarding plants, thus spirits and monsters came into the imagination, some of the oldest being dryads from Greek mythology. In Celtic mythology and Paganism trees often came with magical powers and guardian spirits. Later in pop-culture, beings such as the Treants and Swamp-Thing further popularized the concept of fantastical plants in the human imagination.