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Looking Over Book of Challenges: Cave of the Snake

It's just cover art


A cave system hides a yuan-ti temple.


The caverns being an “empty” maze is fine for this encounter because of the threat of heat exposure. The maze is not trying to tempt players into exploring it, it is an exploration minigame punishing them for wasting time in it.

The “Tactics” section for the caverns does a good job of both providing simple guidelines for using spells/abilities in an intelligent way and not having the yuan-ti suicide themselves on the party when they could join forces with nearby allies.

Referring back to the caverns’ “Tactics” sections for the purebloods at the cobra entrance is good, as is the clear division in approach between them and the halfbloods.

Prying out “eye” gems is one of my favorite forms of monetary treasure.

While it’s obviously adding more work for the GM, not defining what’s beyond the other doors in the pyramid makes it very easy to connect this encounter to greater context. And if that’s not desired, it’s also very easy to remove those doors and make the platform do something else if the puzzle is solved, such as produce some hidden treasure.

I like the explicit mention that the other doors in the pyramid can be bypassed with “the normal methods” in addition to solving the platform puzzle rather than having some contrived reasons why solving the puzzle would be the only way to get through them.

I love that the abominations respond to intrusion by deciding “screw this” and fleeing. Aside from simply being more dynamic than a fight to the death in a relatively empty room, it’s an entirely different challenge to capture and interrogate one or more of them than it is to just fight. It even still works with the fluff in later editions that yuan-ti have no human emotions because it’s justifiable as a matter of survival rather than a choice motivated by fear.

Having six colors of jewels for a puzzle that needs only four inputs for the solution is a clever way of making it harder for the players while keeping things simple for the GM.

The advice to think about how very intelligent creatures would take advantage of their surroundings and pay attention to PC tendencies is good, even if I have misgivings about the rest of the tips on playing very intelligent creatures.


Needing to make a Wisdom check to notice the temperature increasing in the cave entrance area is silly. People are rather sensitive to changes in environmental conditions, even if they may not be able to pinpoint the change exactly. This is made even more silly when the start of the caverns mentions that all characters notice the change, despite nothing of note happening between the two areas.

Given that it isn’t unheard of for yuan-ti to show up in jungle regions (such as when they were first shown in a module), mentioning that “It’s clearly about 90 degrees in these caverns, with a muggy, humid atmosphere” may not be a significant change from the conditions outside of the cave. Better to just make it more hot, humid, and stagnant in the caverns, with the specifics left to the GM.

No details are given for determining when the steam jets happen. The GM should pick something, if only to avoid it feeling like a screw job if it disrupts a spell casting that the players were counting on.

If there’s so much steam in the caverns that there’s no visibility beyond 5’, it should be much hotter in there than just 90 ° (unless that was meant as 90 °C, so 194 °F, but that seems excessive).

Given the limited visibility in the caverns, it’s a shame that there aren’t any confined passages sized for abominations to slither through (and thus forcing humans to crawl through). Adding a couple would be a nice way to increase mobility, allowing for more retreat and flanking options.

The red glow from the iron door gems should be visible from some distance away.

Given that nothing indicates the cobra entrance door shuts and locks behind the PCs when they enter the pyramid, there’s no apparent reason why the abominations would bother with solving the platform puzzle instead of just running away through the caverns.

As ever, I hate using Intelligence checks to let the dice think for the players. I’d consider all of the hints as things the abominations can tell the PCs if captured and questioned effectively.

Changing the order of the jewels for each row of the platform puzzle feels like unnecessary obfuscation for something that’s meant to limit access through a travel hub. I’d have each row show the jewels in the same order and in an orderly fashion unless I was changing it to hide treasure instead (since the added obfuscation would make more sense for a magical safe). In return, I’d halve or even quarter the number of rows (the yuan-ti can get the combination in no more than five rows, after all, so any more beyond that is just adding margin for error for the players).


The intro mentions that this encounter “contains more creatures than [the GM] may be used to running”, but there are just two groups of five creatures and one group of three, with the latter rather unlikely to be fought together with either of the former. By EL 10, I’d expect a GM to be comfortable running encounters of these sizes.

The cave entrance boxed texts have several ambiguous/confusing points. Is the arch the same as the ceiling support beam, or is it a separate piece? If it is the same, does “[m]ade from one solid piece of wood” refer to just the arch or to the arch and the columns together? What is the point of mentioning which way the head is facing in a cave with no branching paths? Does “[t]he walls of this corridor are not the naturally formed stone found previously” mean that the head carvings are worked out of the natural stone or that the carvings are made from different stones that have been brought to this area? Why do some of the heads have “rows of pointed teeth”, a feature of neither humans nor snakes? Is “the hint of a cobra head” referring to the actual head (which has some common structural differences from vipers and nonvenomous snakes) or to the hoods that some cobras have (which are formed by their ribs, not their heads)? What are the “tiny, pointed ears” for, since neither humans nor snakes have those?

Following all of that boxed text with “[n]othing of any real significant can be gleaned from [these details]” offends me on multiple levels.

While I’m fine with “[t]he yuan-ti have adapted to the heat and suffer no ill effects” as a mechanical Hand Wave, the lack of any details or even suggestions about the adaptations is a missed opportunity.

The start for the cobra entrance says to locate it “at the end of any of the cavern corridors”, but then the boxed text mentions it being at a three-way intersection, and the map on the following page has its location defined clearly. Then again, considering the map is titled “Yuan-Ti Maze” (a phrase that comes up nowhere in the actual encounter text), this seems like a case of parts being done at different times and put together without sufficient final revision.

The cobra entrance boxed text mentions “huge cobra fangs” that “look sharp enough to pierce dwarven steel”. For the first part, cobras don’t have huge fangs; vipers do. For the second part, that’s meaningless without suggesting any thickness for the steel.

Needing a Spot check to realize that the range of vision near the iron door is double what it is elsewhere in the caverns is exactly the sort of thing that gives 3E a reputation for being overdefined nonsense.

If “[t]he highest point of the [pyramid’s] ceiling is obscured by smoke”, how come the “pointed ceiling provides immediate evidence that this area is the inside of a massive pyramid”? Even aside from my usual complaint about boxed text dictating what the PCs think, it’s bad writing when two consecutive sentences contradict each other.

The text calls for three abominations, while the monster details call for only two.

With a couple of exceptions (the iron door eye gems and the abomination’s ring), the treasures in this almost are the exact opposite of Ladies of the Lake in that they’re all boring money and equipment. Even those exceptions aren’t much better, but I’m trying to give it the benefit of the doubt.

As written, it isn’t entirely clear whether there is one combination to solve the entire platform puzzle or if each row has its own individual combination. Given that each row can be triggered only once until the whole platform is reset and the combination changes with each reset, one solution for the whole puzzle is the only approach that makes sense.

Starting out the advice on playing very intelligent creatures by saying that all GMs fudge dice occasionally and might struggle with playing such creatures properly if they don’t “cheat” (quotation marks in text) is a bad start. Following it by justifying using the GM’s knowledge of the players’ discussions at the table to make encounters more difficult through illusionism is even worse, in my eyes. That feels like a violation of trust, an abuse of power, and just general poor form (since a GM who lacks the experience and acumen to play such creatures fully is probably also suboptimal with less intelligent creatures and so should look to develop those skills across the board if they want to improve at it, not cheat to seem better than they are). It’s that sort of behavior that leads to trust issues which can cause real harm.


In both general scope (this is basically a small adventure) and actual text length (over four pages), this is one of the biggest encounters in the entire book. There are some very strong parts (turning the maze into a trap, solid tactics for all of the creatures, easy to expand), some parts that feel like paint-by-numbers filler (excessive checks just to have dice rolls, boring treasure just to have treasure), and some parts that feel like they just didn’t care (several contradicting/confusing sections in the text, nearly no information on how the steam jets work, multiple instances of ignorance about basic ophidian anatomy). That said, the weak parts are mostly detail elements rather than problems with the foundation.

Probably the biggest point in favor of this encounter is its flexibility. Not only are yuan-ti versatile creatures in terms of where and how they can be used, but there’s actually not much in the encounter that makes them necessary; replacing them with other intelligent and group-oriented creatures requires some adjustments to the descriptions and tactics, but there’s nothing keyed into special abilities of the yuan-ti. Beyond that, this encounter is pretty clearly meant to slot into a larger adventure about what’s beyond the other doors in the temple (or whatever treasure is hidden by the platform puzzle, for that modification), in which case there are arguments for either keeping the yuan-ti (to add a sense of a greater world beyond the PCs’ influence) or changing them to some other fitting opponents (for thematic purposes or to feature an established opposition faction, for instance). Any sort of fantastical locations can make sense beyond the iron doors; element planes, afterlife realms, primordial fonts of creation, lost continents, or even just distant lands; and going with the treasure reward for solving the puzzle can result in basically anything.

The encounter itself also has a lot of variety in its challenges, showcasing exploration/survival, combat, capture/interrogation, and puzzle-solving. I can’t imagine a player who wouldn’t engage with at least one of those. Even better, there’s very little about the encounter that’s keyed into PC abilities, so it can be used fairly independently from any level scaling considerations. Getting into the temple stealthily and solving the platform puzzle without getting caught is difficult, but it’s doable.

Speaking of which, the main complaint I could see for this encounter is finding the platform puzzle to be too gamey (with reason, frankly, since it does seem like something that’d fit in Silent Hill or Resident Evil). I think it’s fine as a fantastical combination lock as long as the types of gems found elsewhere in the encounter are varied rather than sticking with all rubies as written, but if it still feels out-of-place, it can be replaced with some other compact puzzle without having much other impact.

All in all, even with the sloppy editing and other issues, this is a wonderful encounter. It does need effort to smooth out the wrinkles and figure out how it fits into greater context, but there’s so much great stuff in it that it’s definitely worth using.



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