Mandrake, also known as mandragora is a herb of the solanacea family (and thus related to the nightshades) with a long and arguably infamous reputation in relation to the herbalism and magic around human sexuality and reproduction.
Part of this may be due to the fact that the roots of mandrakes are frequently seen to form crudely humanoid shapes - sometimes visibly male or female to the willing imagination - which the Doctrine of Signatures and similar superstitions would find ample evidence of some great significance. Scientifically, these plants, being solanaceae are also loaded with toxic alkaloids which have potent hypnotic and psychotropic effects, again lending themselves to entheogenic and/or pseudo-medicinal use.
Reputedly mandrake could be used in love potions, potions to promote or restore fertility and general aphrodisiacs - and more mystically could be used in the making of homonculi and similar things. The most potent examples of the species were said to grow beneath gallows on which men had been hanged and some legends suggested that the scream that a mandrake made when uprooted could cause death or insanity in anyone who heard it1.
More aggressively dangerous examples are generally confined to the realms of fantasy, but these include the humanoid roots becoming aggressive creatures in their own right and emerging from the - with or without the shriek - and attacking people.
Game and Story Use
- If you want to use the "humanoid monster" mandrake, consider that it might come from a particularly old gallows variety, fattened on a great many deaths and possibly inhabited by the spirit of one of the deceased.
- Possibly the shrieking mandrake is a specific sub-species, or one that only grows under gallows or in areas of magical significance, with other such plants being merely poisonous herbs. Finding the right sort - of finding the wrong sort by accident - might be interesting. Presumably only the "full fat" variety is any use for real magic.
- Perhaps mandrake is normally only a psychoactive herb, but grown in the right area (such as under a gallows) it adsorbs stolen life energy and becomes the magical, shrieking variety. Let it feed long enough and it becomes the fully mature ambulatory predator…
- Pulling up mandrakes might be an interesting bit of gaming - although modern players will probably want their PCs to use ear-defenders rather than dogs.
- As per the final Harry Potter the shrieks of mandrake might be weaponisable by properly protected persons.