In the 3rd Edition rewrite of the famous module White Plume Mountain, the titular dungeon gets modified highly successfully to use 3rd Edition rules while staying very true to the original version in style. One specific encounter, however, sticks out as a very poor conversion...

Early on, the group is given a crossroads of three directions to choose from to tackle in any order. Almost immediately down one of these paths (canonically the "first" one you're expected to do, if the order it is written has anything to say about it), you encounter a slime trap. The rules state no way to avoid or defend yourself against this trap - simply that green slime falls from the ceiling when an adventurer passes below it, automatically hits them, and deals terrible damage (including Con Damage) continuously unless removed or burned promptly. It will immediately kill most typical adventurers in only a few rounds.

This particular trap offers no saving throw, opposed attack roll, use of trap-finding, or even a spot check. This is not the case for every single other element of the dungeon, which is full of Reflex-Save or Attack roll traps and ambushes that are all labeled and given statistics.

What happened here? Why is this trap so special and hardcore - and one of the very first ones in the dungeon, no less? Reviewing the 2nd Edition version, the trap was similar there (just even more likely to instant kill, what with Save vs Death), but all the other traps were similarly more hardcore, and were revised appropriately in 3rd Edition.

The rules for Green Slime are actually not unique to this dungeon, and are available at the SRD under Dungeons. It says that they hit a 5-foot square and deal their damage and effect there, but no rules are given for any kind of defense. This seems to be a major contradiction in mechanics and style to everything else in 3rd Edition.

Alternatively, are there any fair house rules for this situation? A reasonable spot check difficulty or reflex save ruling for how to avoid this slime?

Clarification: The major facet of the question is the inconsistency of the rules between this trap and all others in the module. 2nd Edition situations are well known for their difficulty, and 3rd Edition for toning down that same difficulty. The fact that this one type of obstacle is the only one that seems effectively "unconverted" in nature is what is being called into question.

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    \$\begingroup\$ First of all, Constitution damage is less likely to kill low level characters than direct damage - even if it's less likely to be cured as fast. Removing the ooze shouldn't be hard so the character shouldn't be going to lose much Con. Unless it deals 2d6 Con damage I don't think the trap is so bad. It consumes resources, yes, and probably forces characters back to town for a while, but it doesn't look so deadly. \$\endgroup\$ – Zachiel Jan 16 '13 at 17:30

As you say, this is how Green Slime is presented in the DMG (3.5e p77, 3.0 p117). Note that Green Slime is considered a hazard, much like a flow of lava, raging river, or 40' pit would be a hazard.

Green slime is green slime. Does the module say the slime is invisible? That the players can't see it? Is there an illusory wall or darkness spell concealing the ceiling? Exactly what is stopping the players from looking around and seeing that the walls and/or ceiling of this room are entirely covered in thick, wet gobs of outrageously neon green slime? Green slime is meant to attack characters that go running down corridors heedless of obstacles or without light sources, or to restrict their movements. Without magical aid or PC stupidity, it's not subtle. Even if the module says "the PCs don't immediately notice" the slime, that doesn't mean it's sequestered. If the PCs say "I'll check the area for traps" or "is there anything on the floor or ceiling?" then they're going to see it. Sometimes you have to read between the lines.

Also, remember that green slime responds to movement—any movement that might be big enough to be food. It need not be a PC. It need not even be alive. Green slime is not cunning. It doesn't wait for the right time to strike. It drops on the first thing of reasonable size that moves underneath it, so it's unlikely that more than one PC would be affected. It would not wait for the whole party to be below it to drop.

Next, most DMs I've played with rule that the slime has to burn through the armor before it deals damage to PCs. The rules aren't clear, but they do imply that this is what happens. Combining that with the fact that it states that fire destroys it (such as a torch) and it can be scraped off during the first round (such as with a torch or dagger), and you see why it's only CR 4 (the same as an 80' pit, or roughly a 20' spiked pit covered with an illusory wall). Green slime is literally defeated by uttering the phrase "I scrape it off with my dagger". This means that, IMX, in almost every instance a player has been affected by green slime the results have been that the PC's armor and weapon have been damaged or destroyed... and that's about it.

Truly, the difficulty of green slime is getting past it once you know it's there. It's still deadly, but you need to find a way to get a lot of fire on the ceiling (burning hands or produce flame) or get it to drop for you to burn ("what did we do with that orc's body?") or find a way around.


To address your first question,

Why is this trap so special and hardcore - and one of the very first one in the dungeon, no less?

Think of the alternative. If the first few traps the players encounter are easily avoidable, or can be shrugged off without too much effort, that sets the tone for the rest of the dungeon. The paradigm becomes one of "Move around and deal with what happens."

But by leaving just one particularly deadly trap right at the beginning of the dungeon, you've set the tone for the players to be terrified and cautious. Now they'll be proactive instead of reactive, and hopefully detect and deal with most traps before encountering them. If one or two traps are missed, it's "Phew, this one didn't insta-kill us... but we still need to be careful!"

I'm not saying one of these is better than the other. It just depends on the type of game you want to run. If you want a typical dungeon crawl then go ahead and houserule the slime to be less deadly. But if you want your players to be shaking in their boots as they inch forward prodding every surface with their 10-foot pole, then I'd leave it alone.

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    \$\begingroup\$ Then why only have one like that at the beginning of only one of the three paths? \$\endgroup\$ – Oblivious Sage Jan 16 '13 at 20:45
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    \$\begingroup\$ This is reasonable logic, but as Oblivious Sage said, it is only technically one of several possible "first paths". The first encounters in the other directions (a pit full of water and a very typical, escapable monster encounter, respectfully) don't do much to set the tone using this logic. \$\endgroup\$ – Southpaw Hare Jan 17 '13 at 0:03

Earlier editions of D&D are known for particularly unforgiving traps. The Tomb of Horrors had many instant-death traps, even right at the beginning (for example, the two false entrances to the tomb, which could easily instantly kill adventurers). But for saving throws and checks for the trap, I'd recommend a moderate-easy spot check DC (the slime shouldn't be hard to spot, and adventurers will usually know to fear slime of any kind which they find in dungeons) and a high Reflex save DC (the slime is clingy, and even if you jump out of the way in time, it might have a chance to latch on).


Its up to the GM to apply their brain in situations like this. If the players say they are checking out the ceiling before entering a corridor, the GM should either tell them what they see (slime covered ceiling) or provide an appropriate spot/search check if the danger isn't obvious. Similarly, a REF save or possibly attack roll is probably in order when the slime starts dropping. The lack of explicit saving throw targets in the module does not mean no saving throw should be offered. It's the GM's game... it's their responsibility to adjudicate fairly. "Because it's not in the book" is not a good excuse.

Don't get me wrong... if the characters are blundering into the hallway without checking/searching first - especially at the beginning of a dungeon - they deserve what they get. Its just that if they do act proactively to search out traps, the GM should deal with that reasonably.

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    \$\begingroup\$ I don't buy this answer. Obviously, GM rulings are an option... But the point of the matter is, this module contains dozens, perhaps hundreds, of individual events (encounters, traps, hazards...), and yet this is the only one of them that lacks normal rules and requires this kind of GM ruling. It's a matter of inconsistency - and a particularly severe one, due to it's fatal nature. \$\endgroup\$ – Southpaw Hare Jan 17 '13 at 23:01
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    \$\begingroup\$ My suspicion is that its just an accidental oversight. Most GM's wouldnt find it to be a big deal because they knew its their job to handle that. \$\endgroup\$ – GrandmasterB Jan 18 '13 at 6:38

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