The book Medusa: The African Sculpture of Enchantment sounds great:
Just as the mythological Greek figure Medusa possessed the extraordinary power of turning onlookers into stone, the stunning African artifacts, masks, and statues showcased in this fascinating book were all created to cast spells on people. The function of these objects was not merely to symbolize a person or thing, but to incarnate a magical power that could act on people and the world during religious and medicinal rituals.Currently 27% off at Amazon.
Mysterious and exceptionally crafted, these masks and sculptures are deciphered by African art specialist Boris Wastiau, who examines their symbolism and ritual usage, and explores the connection between the material and spiritual. Against a backdrop of allegories are more than 100 beautifully photographed works from the Museum of Ethnography in Geneva; Medusa is a comprehensive and accessible introduction to African art.
There's currently an exhibit by the same name at Les Musées de Genève, so I assume it's related to the book. Here's a few masks from the exhibit:
You can see more here.
*Previously: Plush beheaded Medusa.
*Buy African masks at eBay.