Roadkill

S2 E16: While driving down a deserted road, Sam and Dean are startled when a bloody woman, Molly (Tricia Helfer - "Battlestar Galactica"), bolts in front of the Impala, screaming for help from the crazy farmer who is chasing her. After investigating, Sam and Dean discover that the man is actually an angry spirit that kills one person at the same time every year and has decided Molly will be his next victim.