Strange Things Happen When You Sleep In Dungeons.....

Close to death.....out of spells.....out of potions.  Three levels down and 10 hours from the front.  There's no way out tonight.  This place is alive with the dead.  Going into that crypt was a bad idea.  Should have known.....  Those that remain can rest here.  Seems safe enough......  The door bars from the inside.  It's cold and damp; a mixture of mud, blood, and stone.  We try to sleep in the darkest of darks, haunted by sounds that would chill even the gods, blinking in and out of nightmares, regretting the decision to descend.  When morning comes it is still night.....

Sleeping in dungeons would SUCK.

So let's make it suck in an interesting way.....

This is about quality of sleep.  You need to determine every PC's Sleep-Factor, which is simply the percentage of hit points they have remaining.  Example:  PC-1 has 7 hit points remaining out of 22, 7 divided by 22 equals.318, so PC-1's Sleep-Factor is 32%.  PC-1 will have to roll 32 or under on d100 in order to have a successful night's rest.  More about this in a minute.....

Sleep-Factor = percentage of hit points remaining.

Healing Rules.  I think it's safe to say that most old school games award 1 hit point per night's rest, and probably include your constitution bonus if you have one.  Some may also include the PC's level as a bonus.  Some may allow them to roll one hit die.  Healing rules probably run the gamut.

I like: (1 hit point + constitution bonus + level) and will be using this as the assumption for these rules.

Back to Sleep-Factor.  Every PC makes a Sleep-Factor roll (it is essentially your saving throw against a very bad night's sleep.)  If they succeed on their roll, they rest well and gain the normal healing benefits.  If they roll doubles on their success, they get to roll one hit die and add that to their total hit points healed (or you can simply allow them to heal double their amount.)

If they fail their Sleep-Factor roll, they were haunted by restlessness and/or something strange happens, but they still get their healing.  If they fail and roll doubles, something strange happens and they DO NOT recover any hit points.  Roll 1d20 below for Restless Sleep & Strange Events.....

Restless Sleep & Strange Events

1.  Sleep-Walker:  Whether you've ever sleep-walked before or not, doesn't matter, you did tonight.  You wake up the next morning 1d4+1 rooms away to the (1d4) 1--North, 2--South, 3--East, 4--West.  Good luck.

2.  Infection:  Some cut or wound you received earlier has become infected.  You were tossing and turning and sweating all night.  In the morning you feel like crap and suffer disadvantage on all saving throws for the next 4d6 hours.

3.  Bug In Your Ear:  Madness and pain ensue as you awaken to the thunderous sound of an insect buzzing inside your inner ear canal.  Your screams are loud.  Until the bug is removed, check for wandering monsters every 1d4 rounds.  The players will have to get creative to solve this one.....

4.  Seduced By A Succubus:  In your weakened state, you've been targeted by a Succubus, see this post.....Succubus

5.  Gremlins:  You had the strangest dream of weird little goblins crawling all over you, giggling and snorting, poking and prodding.  Soon after waking, you realize your favorite weapon (or spell-book) is gone.  Unbeknownst to the PC, the item is hidden in a tiny secret chamber in some room in the dungeon.  There is a 1 in 6 chance that any particular room is that room.  They still have to find the secret door.....

6.  Thief:  You wake to discover a prized item of yours is now in the possession of one of your companions who insists it is theirs (they must save vs. spells to willingly give it back, otherwise they protect it as if it's their prized possession, in fact, they dreamed that you were trying to steal it from them.)  If you're a Thief the situation is reversed, whether you remember it or not, you're the one who took the item.

7.  Visions Of The Reaper:  During the night you wake up to the bone-chilling vision of The Grim Reaper standing over one of your companions (roll 1d6 and count leftward to determine the PC.)  That PC now has disadvantage on their next 2d4 death-saves.

8.  Your Future Corpse:  Your future rotting corpse (or the corpse of a best friend) visits your dreams (nightmares) and warns you never to leave this room.  You are convinced this was real (and maybe it was.)  In the morning, under no circumstances will you leave this room.  You are petrified with fear and have to save vs. fear (petrification) once an hour.  You need 3 consecutive saves in order to get a hold of yourself.  Only then can you willingly leave.  If forced to leave, you will resist and scream maniacally, forcing a check for wandering monsters every time.

9.  End Of The Road:  In the morning, your companions awaken to discover your corpse with an expression of indescribable terror locked on your face. (Optional of course, you may roll again and let this be someone else's nightmare, but you have to roll twice.)

10.  Revelation:  You dream of the exact location of a marvelous treasure located somewhere in this dungeon.  The DM must let you read the entire contents listed under that room.  And you thought you were leaving.....

11.  False Revelation:  Your dreams reveal that your hearts desire is in danger 2d6 rooms from here (a room you haven't been in yet.)  Your friends may have other plans, but that's where you're going.....and nothing will stop you.  Unfortunately, the room already contains something else.....Of course, you never know, if the DM wants to make things interesting.....

12.  Sabotage:  You don't remember doing this, but you gathered up all the party's rations (including water) and smeared them all over the walls in a nihilistic fit of utter frustration.  They know it was you because you're a mess of food particles.

13.  Preternaturally Tired:  You will sleep for 1d4+1 more days after which you will rise completely refreshed of all wounds and ailments.  Until then, you sleep.  No matter what.

14.  Murderer:  If you have henchmen or NPCs with you, one the strongest of them (as in level) is found dead in the morning from stab wounds.  You killed him.  You know this.  You vaguely remember the act and the cryptic voices emanating from the walls that commanded you.  The room is indeed haunted and this will happen every night the party sleeps here.  If there are no henchmen or NPCs, another PC (randomly determined) awakens to you holding a dagger to their throat.  You have to save vs. spells to avoid trying to kill.  If you fail, roll initiative.....

15.  Careless Mistake:  You get up and unlock the door or deconstruct whatever barricades the party set up.  Roll for wandering monsters.  If one is rolled, it's gets the benefit of surprise.  If there is no encounter, the party will surely ponder why the door is wide open.

16.  Tongues:  Everyone is roused by the sound of you speaking in tongues.  You utter this strange language for 3d10 minutes before falling silent.  Magic-Users can make a language roll (or save vs spells with advantage) to recognize the language.  It turns out that you are revealing something juicy about the dungeon and the DM should reveal something useful.  However, everyone is so unnerved by this experience that they all have to save vs. paralysis or fail to recover any hit points from their night's rest.

17.  Insomnia:  You didn't sleep a wink, or so it seemed.  You're exhausted and have disadvantage on all attack rolls for the next 4d6 hours (if you're a spell-caster, your targets have advantage on their saving throws.)

18.  Rodents:  You wake up to rodents nibbling on your fingers, toes, or ears.  You kill them easy enough, but now you have to save vs. disease (poison) or you will wake up deathly ill -- so weak you're unable to move.  If infected, you're beyond useless and need to save vs. disease every day, 2 failures in a row equals death, 2 successes in a row and you recover.

19.  Out Of Body Experience:  Your soul left your body and went on a little Astral Journey through the dungeon.  The DM must hand you the complete map of the dungeon and let you view it for a number of seconds equal to 3d6 + your level.  You're exhausted and recover no hit points, but, you have a percentage chance equal to your Sleep-Factor of knowing the contents and secrets of any room before you enter it for the entire next day, beyond which, this knowledge fades.  The DM's gonna love you.....

20.  Double Nightmare:  (DM rolls some dice as if checking for wandering monsters.)  A huge, 8HD, AC: as plate, 2d6 bite/poison or die Spider, smashes into the room.  Everyone wakes up, roll initiative and play the fight out as normal.  The spider keeps targeting you and just as you roll a poison save, you wake up!  Everyone is sleeping peacefully and all is well.....until the room begins filling with black water furiously fast.  Your companions won't wake up and if you get close enough to shake them, you notice they're skeletons!.....It's morning, your companions wake you from a screaming nightmare.  You get 1 hit point for your rest.

Have the players do the rolling, but as a DM, you must keep the contents of this list secret, because spoilers.  You probably don't want to over-use this idea.  Maybe once per dungeon. And maybe only for characters whose Sleep-Factor is below 50%.

Another thing, players will usually set watches throughout the night.  For wandering monsters, taking turns on watch can help prevent a surprise attack, but for the purposes of this exercise, watch doesn't matter.  These events are mysterious and can happen quickly, in the blink of an eye.  People on watch are notorious for nodding off, if even for a moment, and they never admit it (seriously!)

"It didn't happen on my watch!"