A werewolf is a creature from folklore and scary stories: a person who transforms into a wolf or wolf-like monster, usually when the full moon rises. During the transformation, the person grows fur, sharp claws, and fangs, and may lose control of their human mind, becoming dangerous and wild until sunrise returns them to human form.

Werewolf legends appear in cultures around the world, from ancient Greece to medieval Europe to Native American traditions. The stories vary, but they often explore the tension between civilization and wildness, between our rational human nature and our animal instincts. In some tales, people become werewolves through a curse or a bite from another werewolf. In others, they transform by choice using magic.

Modern movies and books have made werewolves popular characters, sometimes portraying them as tragic figures struggling to control their transformations, other times as straightforward monsters. You'll also see the term lycanthropy, which refers to the condition of being a werewolf or believing you can transform into a wolf.