The Mandrake is also known as Mandragora, is a plant which has a root that looks like a human (like a baby when the plant is young, but maturing as the plant grows). When mature, its cry can be fatal to any person who hears it.
Mandrakes are part of the second-year Herbology curriculum at Hogwarts. In 1992-1993 the school's growth of Mandrakes served the additional purpose of making a Restorative Draught to revive all those who had been Petrified during the Chamber of Secrets openings.
Mandrakes contain deliriant hallucinogenic tropane alkaloids and the shape of their roots often resembles human figures, they have been associated with a variety of superstitious practices throughout history. They have long been used in magic rituals, today also in contemporary pagan traditions such as Wicca and Odinism.