The Curse

The curse is a frequent literary element used in magical fantasy and especially fairy tales. The curse often takes the form of transfiguring a human into an animal/beast (see Beauty and the Beast) or hampers the progress of a protagonist (see Cinderella) and can be placed by witches, fairies, gods, and other magical creatures.

Beauty by Robin McKinley
Blade of Fire — Stuart Hill
East by Edith Pattou
Ella Enchanted by Gail Carson Levine
Enchantment by Orson Scott Card
Light of the Oracle by Victoria Hanley
Mira, Mirror — Mette Ivie Harrison
Plague of Sorcerers — Mary Frances Zambreno
Princess and the Hound — Mette Ivie Harrison
Wicked Lovely — Melissa Marr