Fear in a dream often names a threat you sense but haven't consciously articulated -- something that feels like it could harm you, even if you can't point to exactly what. The specific danger in the dream matters less than the instinct to protect yourself, which is usually the real message worth paying attention to.
Anyone who pretends to gather the powers of the stars is forced to assume their character. - Picatrix (Andalusia, ~1000.AD)