D&D 5E How do you run Perception and the Gelatinous Cube?

mrpopstar · Jan 5, 2017

Don't forget that only those characters focused on watching for danger contribute their passive Wisdom (Perception) scores to the group’s chance of noticing hidden threats, and you might decide that a threat can be noticed only by characters in a particular rank of marching order.

rgoodbb · Jan 5, 2017

Yeah, I was thinking that any 1st level party with either a Cleric, Druid, Monk, Ranger or Rogue (with maybe expertise) could plausibly auto-detect a G.C. all the time. This would make one of this iconic monster's main shticks rather redundant.

Ps. Brand new players. Wouldn't know about the telling signs, although I suppose if they asked for a nature/survival check, that might do it.

Thanks for all the replies.

DEFCON 1 · Jan 5, 2017

Shadowdweller00 said:
Yeah, one of the things that bugs me about 5e (and related systems) is that Perception is kind of the God Skill. I don't have a good fix for it unfortunately.

Split it in half by having only living things that can move around, make noise, have a scent and/or and show signs of passage (IE anything that makes DEX Stealth checks) get found using Perception.

Anything that are inanimate or objects and hidden/disguised from view... like tripwires, traps, secret doors, secret compartments etc... get found using Investigation.

Perception looks for the wider signs of movement, Investigation looks for the close-up details of things different than their surrounding area or background.

iserith · Jan 5, 2017

rgoodbb said:
Do you ask for perception checks and alert the PC’s that there is something to spot?

No. IF the players have established their characters are keeping watch for traps and monsters while traveling the dungeon (as opposed to doing any activity that distracts from that), then I use passive Perception to resolve uncertainty IF I'm not sure the PCs definitely see or definitely do not see the gelatinous cube, based on the specific context at that time.

rgoodbb said:
Do you rely on Passive Perceptions and anyone high enough just spots it?

Yes, IF as above the PCs have stated they are alert to danger. If they're doing just about any other task, then they are simply surprised by it.

rgoodbb said:
Or do you rule that if no-one is actively searching then they can just walk right into it if they move into its space?

IF the players are not having the character stay alert to danger, then yes. However, it's worth nothing that a "passive" Perception check means you are actively searching for danger if you are keeping watch while traveling the dungeon. "Passive" refers to there being no die roll. The characters are actively remaining alert for trouble.

iserith · Jan 5, 2017

Warmaster Horus said:
You may not spot the Cube, but instead notice signs of it's occupation - area is remarkably clean, slight acid-washing of a piece of metal on the ground, etc. Maybe toss that out to players with a good enough PP and let them work it out from there. That will usually be enough.

What @Warmaster Horus is referring to here (bolded) is called "telegraphing." That is, providing clues of possible danger to the PCs and letting them take action to avoid a potentially disastrous fate. I recommend providing some level of clue without a check (passive or otherwise) and then ask what the PCs do. Further investigation to draw conclusions based on the evidence may call for an ability check of some kind. If they start keeping watch for danger (assuming they hadn't already established that), then you can apply passive Perception to see if they spot the gelatinous cube while they continue their travels in the dungeon.

Telegraphing is what in my view makes a gelatinous cube encounter - or really, any encounter with a hidden monster - fair. Without some clues heralding potential danger ahead, the players can wander blindly into an unavoidable problem and that's neither fair nor fun in my opinion. As I see it, this game is all about the ability of the players to make meaningful decision and without sufficient information, it's just a guessing game... or a total screwjob when the "gotcha" tactics of the DM takes out a character.

rgoodbb · Jan 5, 2017

Oh, OK. Cheers for all the info. Still learning this side of the game, thanks for educating.

iserith · Jan 5, 2017

rgoodbb said:
Yeah, I was thinking that any 1st level party with either a Cleric, Druid, Monk, Ranger or Rogue (with maybe expertise) could plausibly auto-detect a G.C. all the time. This would make one of this iconic monster's main shticks rather redundant.

I think the trap a lot of DMs fall into is treating passive Perception like an "always on radar." That's not how it works in my view. You can only perform one task at a time while moving about. One of those tasks is "Keep Watch." But there are other tasks like navigating, foraging, tracking, drawing a map, searching for secret doors, etc. The key is making those tasks as attractive (read: beneficial) to the PCs as possible so that they'll risk not keeping watch.

For example, in my dungeon-delving campaign, a complete map of a dungeon level is worth 100 gp x the level of the dungeon. So if you map the Soul Trap Layer on level 5, you can sell that back in town for 500 gp. This means there's always some character that will draw a map rather than keep watch for danger, opening up that character to being surprised. In the Shade Garden of Muscaria the Inscrutable, foraging can net you some magic mushrooms that have potent divination abilities which allow the PCs to preview other parts of the dungeon. Therefore, someone will tend to forage instead of keep watch. Secret doors are known to either be short cuts that can allow the PCs to skip past trapped areas or to get from level 3 to level 5 quickly (for example), so naturally one PC is going to want to look for those at the risk of being surprised.

In short, if you don't make other tasks as attractive as keeping watch for danger, then all the PCs will just keep watch for danger and the high Perception PCs will usually spot all the hidden traps and monsters (but not secret doors!). Which is fine, of course, if that's what they want to do. I just prefer some meaningful trade offs in my games.

rgoodbb · Jan 5, 2017

isereth.

This is all very helpful insight. Thank-you.

Tony Vargas · Jan 5, 2017

rgoodbb said:
As the title says, I'm not sure exactly how to approach this encounter. I don't need help on where to place it and what sorts of traps to use it on etc., just the initial do you spot it.

In the olden days it was something like "90% undetectable," it was a one-off % resolution rule. The classic game was full of stuff like that. But the point wasn't the roll, the point was to describe to the players:

"You see a skeleton floating towards you down the corridor!"

And see what they did. If one of them rushed forward to attack it :schplooorgh!: paralyzed. Gotchya.

Once you've done that you never need to use a Gelatinous Cube again.

Do you ask for perception checks and alert the PC’s that there is something to spot?

Do you rely on Passive Perceptions and anyone high enough just spots it?

Or do you rule that if no-one is actively searching then they can just walk right into it if they move into its space?

You're the DM. In 5e you decide how to resolve any given action. If the action is walking down the corridor, when you know there's a Gelatinous Cube filling that corridor, you decide whether to call for a check, make a check vs a passive score, or narrate the result...

... as a general rule of thumb, I personally think it's a good idea to either narrate a result or call for or make a check vs a DC. I don't think comparing two passive scores is worthwhile (so avoid just comparing passive perception to a DC to detect), and, on the other extreme, feel the same way about the very swingy contested check. If you don't want to call for a check, make a check using passive perception as the DC or just narrate what happens.

LordEntrails · Jan 6, 2017

I use passive Perception unless they are looking for something along the lines of a GC. Then, even if they do make the check. I don't say "You see a gelatinous cube".

Instead I say something like, "You notice the floors here are spotless." Or, "The air in the section seems stagnant and bitter." Or....