A shadowy figure

It is late at night as you walk home.. The day had dragged on longer and longer while you were at work, and the relief of finally walking home is upon you. After about 20 minutes into your daily hike, something catches your eye, passing by an alleyway. After just a brief moment it is gone, and everything in the night atmosphere is still once more. The incident worries you, however, and you debate calling your friend to pick you up and drive you to your house.