The one part of the dungeon your heroes are most in contact with (unless they are blessed with permanent levitation or wings) is the floor, yet all too often it is given barely a mention during the game. It’s just there, trodden on and forgotten.
It doesn’t have to be that way, of course. The floor of a dungeon can (and indeed should) be just as important a feature as any other element that makes up the adventure. Here’s a few ideas to spark your own creative juices.
Difficult and dangerous terrain
The easiest way to make the floor something more than just ground to walk upon is to turn it into a tactical consideration. Patches of rubble and detritus make for uneven footing, especially in the midst of battle. In D&D Next terms this could mean Speed is halved and Disadvantage to attacks, making it an ideal place to force your foes to onto. Imagine a room with a small patch of clear ground surrounded by uneven rubble around the walls. Whoever holds the ground has a distinct tactical edge.
Taking it a step further and the floor can be a downright dangerous place on which to stand. Whether it is grasping skeletal claws rising out of the earth tearing at limbs, a bubbling acid pool, the sheer burning cold of Frostburn Ice or worse, the game effect will be much the same – in addition to the area counting as Difficult Terrain, if you enter the area (and each round spent within) make an Attribute Save or take damage. The type of save depends on the nature of the terrain; a DEX save would be appropriate for most types of Dangerous Terrain, but a CON save would be more suitable for something like Frostburn Ice or similar, and perhaps even a WIS Save against the sanity-threatening cries of a floor covered in Screaming Maws.
Glass ceilings, glass floors
Few places are more frightening than the future. Imagine a dungeon where every single room, corridor and area has floors of glass allowing the party to see what awaits them in the lower levels. Demons could look up licking their lips at the prospect of fresh souls on which to feed while the heroes gaze back knowing full well that what awaits them knows they are coming.
Now picture a 50 level dungeon with glass ceilings and floors throughout. It’s a deadly Inverse Skyscraper Of Doom where the denizens of each level look up with hunger and down with fear. Replace “glass” with a fantastical equivalent (sheets of pure invisible magic, stained or volcanic glass or even diamond!) and you have an epic setting for a campaign-length dungeon crawl.
If that’s too much glass for your taste imagine a room containing a single circle of glass embedded into the floor. At first glance this looks like a scrying pool but it’s really a view directly into the room below through which our heroes can see an ongoing ceremony to some vile deity. It is also the only way down to the level below. If the party wishes to descend to the next dungeon level (and they will) they will need to somehow break the glass and literally crash the ceremony. Nothing starts a fresh dungeon level better than heroes leaping into battle!
Tracks in the sand
Sand is wonderful stuff. It shifts and curls with the passage of air and time, hiding the past but also revealing recent events. A sand-coated dungeon floor can reveal much about whether a particular corridor has been recently travelled and by what. A skilled tracker or Ranger should be able to discern from the swirls in the sands the number and type of foes along with what direction they travelled. Sand is also great for leaving false tracks so a wise groups (the party or particularly smart monsters) could brush away their own trails or even wear oversized boots to make it look like the dungeon has been invaded by giants.
Sand can also count as difficult terrain (see above) as high dunes are difficult to find purchase upon, and even be dangerous terrain if the sand is deep and there is a risk of it pulling a hero in. Woe betide a party who discovers that a dungeon with 10′ high ceilings is really a 20′ high dungeon covered in a 10′ layer of sand. Every step could well be their last and the entire dungeon floor is effectively one huge pit trap. Good luck with that.
One particularly useful spell in a sand-filled dungeon is Create Water. Given sand of sufficient depth this simple spell effectively becomes Create Quicksand and the cunning spell-caster can set Quicksand Traps to ensnare wandering monsters. Just make sure you don’t forget where they are.
(with apologies for that pun) Groundfog, the staple of Ravenloft adventures everywhere, is a great way to add atmosphere and mystery to a dungeon. Low-lying swirling mist and fog can hide a myriad of secrets in its shallow depths including pit traps, levers, scurrying giant rats and dead (or undead) corpses of part adventurers.
If can also be a hazard in its own right with the noxious or enchanted gasses forcing anyone who is knocked prone to make a CON save or suffer the effects of the fumes. This could mean succumbing to the effects of a Sleep spell, taking damage, suffering a coughing fit that grants Advantage to all attacks against you, or whatever else the GM can come up with. A particularly wicked GM could say the groundfog is the Mists of Paranoia and any who breathe in the fumes see their friends as foes until they make a CON save. I couldn’t possibly condone such tricks, of course.
History, mystery and clues
Finally, even the simplest of dungeon floors can tell the best tales. The whole area could be composes of an intricate and beautifully coloured mosaic that tells the story of the original purpose of the dungeon, perhaps giving the adventurers some clues along the way. Age and vandalism may have obscured the meaning, but even those could reveal something about the state of the dungeon in recent times. An ancient temple dedicated to the God of Peace that has been desecrated by followers of the Vile Goddess of Destruction may have once contained a floor mosaic showing whole nations laying down their arms, but now this has been altered to show them burying their weapons in their foes (and each other). This could be a clue as to how the heroes could summon the aid of the God of Peace himself………
Talking of clues, mosaics make terrific centrepieces for locked room challenges. Your heroes could enter a room only to have all means of exit suddenly close. On the floor is a mosaic, but it’s missing a piece and appears jumbled. Statues around the room come to life and start attacking. Can the heroes defeat the statues and fix the sliding puzzle mosaic to open the doors at the same time? A cunning DM could pull out a real sliding puzzle for the players to try to complete during the battle. Have fun with this one.
I hope this gives you a few ideas and food for thought. Till next time!