Combat in D&D and its various descendants is abstract for the most part, making it fast (well, except in 3E) and easy to run, and thus pretty fun to play. So how about using abstraction to introduce dangerous battlefield conditions into a fight?
While some battlefields may be perfectly safe to fight in, one can expect many fights, given where they occur and the genre in which they exist, to be fought in dangerous spaces. The floor could be slippery, there could be a fire pit in the middle of it, the roof could be caving in – just use your imagination.
Actually staging a combat in such a dangerous space can be tricky, though, because the combat rules are abstract. You can use a battle grid and miniatures, but sometimes they are feasible, or you just don’t want the bother.
One way to get around this is to extend the abstraction of combat – Armor Class, hit points, etc. – to the ground itself.
As the Referee, you pick a number from 1 to 20. This is the unlucky number. When this number is rolled during combat – attack rolls or damage rolls – the roller of the number suffers an effect tied to the battlefield.
For example – the room in which a fight is taking place has a fire pit in the middle of it. The pit is about 2 feet deep and there are hot coals in the bottom of it. The Referee decides a roll of ’10’ (unmodified by anything) means somebody has stepped into the pit and burned themselves for 1d4 points of damage. He also decides this damage cannot reduce them to less than 1 hit point, and that the unlucky combatant must pass a saving throw or suffer a penalty to movement for an hour due to twisting an ankle or burning a foot.
Now – this is key – it is probably a good idea to let players know what the unlucky number is, and what can happen (in general terms) when it is rolled. Why? I’ll let Alfred Hitchcock explain:
“There is a distinct difference between “suspense” and “surprise,” and yet many pictures continually confuse the two. I’ll explain what I mean.
We are now having a very innocent little chat. Let’s suppose that there is a bomb underneath this table between us. Nothing happens, and then all of a sudden, “Boom!” There is an explosion. The public is surprised, but prior to this surprise, it has seen an absolutely ordinary scene, of no special consequence. Now, let us take a suspense situation. The bomb is underneath the table and the public knows it, probably because they have seen the anarchist place it there. The public is aware the bomb is going to explode at one o’clock and there is a clock in the decor. The public can see that it is a quarter to one. In these conditions, the same innocuous conversation becomes fascinating because the public is participating in the scene. The audience is longing to warn the characters on the screen: “You shouldn’t be talking about such trivial matters. There is a bomb beneath you and it is about to explode!”
In the first case we have given the public fifteen seconds of surprise at the moment of the explosion. In the second we have provided them with fifteen minutes of suspense. The conclusion is that whenever possible the public must be informed. Except when the surprise is a twist, that is, when the unexpected ending is, in itself, the highlight of the story.”
When the players know the unlucky number, every dang roll has some tension packed into it. You know how everybody stared with wide eyes and holds their breath when somebody has to roll a crucial saving throw or attack? You can bring a little of that to every roll during one of these fights, but only if people know the unlucky number.
A few things to consider if you decide to use this notion:
If the unlucky number is low, it means it has a more likely chance of coming up, since both attack rolls (1d20) and damage rolls (d4, d6, d8 etc.) can trigger it. If you want the effect to be more rare, make the number higher than 10.
Higher numbers also mean success can be tinged with failure; lower numbers can rub salt in the wound of missing an attack.
You can have multiple unlucky numbers. In the example above, the roof might also be in danger of caving in, so a ’10’ means stepping in the fire pit and a ’17’ means roof tiles fall on a person for 1d4 damage.
The effect can also be a time track. Using the “roof falling in” example above, each roll of ’17’ can bring the roof closer to collapsing entirely on the people in the room. Maybe it takes 3 such rolls before it happens. This introduces some great tension into the fight, and requires players to gamble a bit every time they roll the dice.
You could, maybe even should, permit people a way to avoid these unlucky numbers. Maybe they have to reduce their movement rate or accept a penalty to attack.
Whatever the unlucky number, carry the attack and damage roll through completely before the dice roller suffers the consequences. In other words, if the attack roll brings up the unlucky number AND scores a hit, the hit counts and damage is rolled before the unlucky attacker burns himself, slips, etc.
One could also use this to simulate the danger of engaging giant monsters, with a chance of being stepped on or knocked into or of a randomly flailing tail connecting for damage.