There's this idea I've had in the back of my head since 0.7. What if at night time there would rarely be a creature that mimics the red light of a sattelite, and if you get too close it eats you or something? There would have to be some slight differences with the red light so you aren't just playing a guessing game if you don't have the digital map or don't perfectly remember the layout of the world. Maybe for example it could flicker ever so often or the tone of red is slightly different?