Domesticated sheep have the propensity to follow each other into downright dangerous situations and be herded by the most innocuous of shepherds, so it's no surprise these sheep formed an ovine circle of death around one unlucky automobile. They do have plenty of reasons to hate humans, after all.

This scenario brings to mind the Godmonster of Indian Flats. Also, I'm pretty sure this is what happens when a wizard mixes a polymorph spell with an aura of protection. Hat tip to Morris!