When the sleep action is performed, Red will make camp and any nearby monsters will be attracted. If the sleep is not disturbed, the game will fade to black and show Red's dream thoughts. These are similar to the messages from blood on the walls. In Caves or Chaos, the Balrog will be able to enter your dreams, signified by red text and sinister messages. Upon awakening from one of these sleeps, a Horror will spawn.
Since sleeping involves the core mechanic of health management, sleeping strategically is important. When first going to sleep, make sure that you are in a safe location. Various acceptable spots are listed below:
- The top of a ladder on a platform accessible only by that ladder. This way monsters will not be able to reach you.
- A cleared level, preferably near the stairs. If a Horror spawns, you can escape down the stairs easily.
- The Overworld or Underworld. These places can never spawn Horrors and will always be safe to sleep in as there are no monsters. Of course sleeping in the Overworld is unnecessary due to the healstone, but this can be one of the few uses for Underworld portals.