Murderous Car Headlights

Effects
Though disattached from the battery, these car headlights flash bright whenever someone turns their back on them. If the user looks at the resulting shadows, a figure with a raised knife will appear to be right behind them, about to plunge their knife down. Whirling around will show no one is there and will simultaneously turn off the headlights. No one has ever kept their eyes on the shadow to find out what happens when the lights stay on.