Would it be ludicrous to have some traps do percentage based damage vs players? I know some traps aren't really going to threaten players of all levels equally or at all. A small pitfall trap or poison dart trap shouldn't be a big worry for a level 16 fighter. However say a huge spiked pendulum that would very nearly vivisect most characters maybe it would do 1/2 your hp in damage if it hit you.
Has anyone ever tried anything like this for certain traps? Would it perhaps work better with a degrees of success framework? The worse you fail the more damage it does?
I am not sure this would work at all just kinda curious if it's even an idea worth pursuing. Maybe I'm better of using something like 4Es leveled traps and hazards. Or maybe someone already has done something similar?
Percentage? No, I think that goes against the grain of how hit points work in D&D. PCs or monsters with more hit points simply are less likely to be killed, and the measure of the lethality of things in D&D is (generally) expressed by giving absolute numbers to damage (e.g. a claw that does 2d6+7, not a claw that does 15% of your hit points in damage).
That being said, it is expected/presumed that in deadlier locales/settings, the obstacles will themselves be deadler. The most obvious example might be that a standard, less-lethal dungeon might have pit traps 10' deep. For a more dangerous place, the pit traps might be 50' deep with poisoned spikes and spectres! The second trap is instrinsically more deadly, but it still does not do percentage-based damage.
Sure, why not? Just present the damage numerically instead of as a percentage and the players will never know or care.
Because more hitpoints are supposed to make you tougher. Having traps do percentage based damage is the same as having monster with AC value of "can be hit only by a natural 18 or more on the attack die".
So, why not? Because it is a dick move and most DMs are not aiming to be dicks. The players will know and care the moment the 18 Con Dwarf Barbarian and 8 Con Elf Wizard (without feather fall) fall in the same pit trap and both of them nearly die with the barbarian taking way more damage than the wizard's maximum hit points.
Other than that - yes, at higher levels if you want the traps to be a real danger instead of a nuisance - they should do more damage.
As a rule of thumb I use traps with an effect/damage comparable to a spell of the highest level a full spellcaster from the PC level can cast as deadly traps and comparable to a cantrip from the highest level a spellcaster from the PC lvl can use as a dangerous trap.
It is also important to remember that usually traps are not made to guard specifically against the PC. If a tribe of goblins have suffered from kobold attacks in the past - they will probably mostly have pitraps that deal about 10 damage on a failed save and about 5 hp on successful one, so that they are protected from a 5hp kobolds in the most efficient way possible.
They won't have prismatic spray squirting from the walls that can incapacitate a lvl 6 barbarian.
I think it's a REALLY COOL idea and very unique. My caution is: Don't do this all the time, or for every trap. Throw it in twice a campaign, max, or when you REALLY want to demonstrate its impact (say, before a weak BBEG's throne room to compensate for his lack of power but large intelligence?)
Reminds me of the "Demi" and "Gravity" spells from Final Fantasy. I like this a lot.
(also, for people clamoring that it goes "against the spirit of HP/5th ed/reasons" it should be noted there IS precedence. Going to 0 instantly, whether dead or dying afterwards, what else is that but reducing your HP by 100%? 
)
I wouldn't do percentage personally, but it's your choice.
I would make the traps bigger and better though. A 17th level fighter shouldn't fear a 10' pit trap. He's experienced and understands how to easily roll with the fall, avoid damage and land correctly.
However, the same fighter would fear (more) a 60' pit trap into a pool of acid that destroys his armor and flesh alike...for 3d6 blunt dmg fall (halved for landing in liquid) plus, say, 5d8 acid damage each round an armor loses 1 AC per round as well. That's just my thoughts.
I think I'd probably just calculate the average hit points of the party and come up with a damage dice expression that averages that value.
Players would probably be more on board with a static "half your hit points zapped" if it were a magical trap in some fashion, however, such as a soul-sucking necromantic glyph or the like.
Illusionism is an important and extremely useful tool as a GM when it's done properly. Don't tell them it's a percentage and it's a non-issue. If the DM's goal for the trap is to balance it to do half damage to whoever falls in it, then this is a perfectly reasonable way to do so. All the OP is trying to do is balance the encounter by another method. Sounds fine to me - people change the RAW all the time to suit their needs.
The idea that characters taking different amounts of damage from the trap will break the suspension of disbelief is nonsense. What do you think happens if the pit does 4d6 damage? One character might take 6 damage while the other takes 22. If the barbarian takes more damage than the wizard, it's because he landed on his head while the wizard landed on his butt - not because of where the numbers came from.
The important thing is that it really doesn't matter one bit to the player's entertainment from the adventure. All that's actually going to happen in the game is that the 50 hp character is going to fall in the trap and take 25 damage. In the end no one is going to really care if that number is coming from a random die roll, a static amount, a percentage, was pulled from the GM's butt or was carefully crafted from a complex formula based on gravitational pull vs. the weight of chain armor. The story will still move on just fine regardless.
The only reason I wouldn't do it (and usually prefer random die roll damage) is because I would want the amount of damage to be a surprise to me too. But that's just personal taste. I don't like to use the static damage from monsters, either.
Actually, it does matter from the players' side. Don't forget that the players, if they are any good, will try to interpret and extrapolate from the information they have in order to play better. If the person who succumbs to a trap takes 25 hit points, but behind the screen that's just 50% of current (or max, or whatever) hit points, the players will still make decisions based on the only thing they know, i.e. that this is a crazy deadly trap and they need to avoid it like the plague, especially to protect their lower hit point PCs. That is, you may very well (i.e. likely will) be telegraphing information to the players that isn't there. Players do generally know how many hps their PCs have, and they need to make strategic decisions based on hit points. Using "illusionism" in this way actually confuses the players and doesn't let them play as effectively.
Llenlleawg wrote:
Llenlleawg wrote:
Mister_Grizz wrote:
Gnarl wrote:
Keep in mind this will make the danger level much greater and much more "hard core" like 1E or 2E.
As long as you are OK with the possibility of killing off players more easily and as long as the players want this type of game go for it.