D&D 5E Toll the Chest

[Maxperson]

It’s Stealth.
“Make a Dexterity (Stealth) check when you attempt to conceal yourself from enemies...”

Yeeeaaaah, conceal means hide from view. It's not Stealth at all, per RAW. You really need to re-read Stealth, Hiding and Deception.

 

[Paul Farquhar]

It’s Stealth.
“Make a Dexterity (Stealth) check when you attempt to conceal yourself from enemies...”

If the mimic was concealed it wouldn't work, since no one can touch a chest they cannot see.

 

[Maxperson]

If the mimic was concealed it wouldn't work, since no one can touch a chest they cannot see.

Yeah. I'd also love to see @Hriston argue to his DM that his PC using Alter Self should be using stealth during his attempt to fool an NPC into thinking he's someone else.

 

[Paul Farquhar]

So...how does one avoid being surprised by a Mimic? If you can't tell what it is, and even being suspicious and testing it isn't sufficient, does the creature always have surprise?

You would think that would be reflected in it's stat block.

The DM determines who might be surprised. If neither side tries to be stealthy, they automatically notice each other.

-Core Rules​

The mimic is not trying to stealth, therefore there is no surprise round. Everyone takes there turn as normal. However, the PCs may not be aware of what they are fighting, and therefore not know what to target. Example below. If the players touch the mimic before combat starts, then they make a save against being stuck - this does not require an initiative roll, it happens outside of combat.

Huge Spoiler for Rime of the Frostmaiden:

Spoiler: Huge Spoiler for Rime of the Frostmaiden

In Chapter 7 of Rime of the Frostmaiden. The party are searching a museum. They enter a pillared hall with a stuffed Phaerimm hanging from the ceiling. The ranger says "I take cover behind one of the pillars and shoot at the thing hanging from the ceiling". Initiative is rolled, and the ranger puts a couple of arrows into the very dead phaerimm. Then the giant spitting mimics which where disguised as pillars take their turn...

 

[James Gasik]

The DM determines who might be surprised. If neither side tries to be stealthy, they automatically notice each other.

-Core Rules​

The mimic is not trying to stealth, therefore there is no surprise round. Everyone takes there turn as normal. However, the PCs may not be aware of what they are fighting, and therefore not know what to target. Example below. If the players touch the mimic before combat starts, then they make a save against being stuck - this does not require an initiative roll, it happens outside of combat.

Huge Spoiler for Rime of the Frostmaiden:

Spoiler: Huge Spoiler for Rime of the Frostmaiden

In Chapter 7 of Rime of the Frostmaiden. The party are searching a museum. They enter a pillared hall with a stuffed Phaerimm hanging from the ceiling. The ranger says "I take cover behind one of the pillars and shoot at the thing hanging from the ceiling". Initiative is rolled, and the ranger puts a couple of arrows into the very dead phaerimm. Then the giant spitting mimics which where disguised as pillars take their turn...

LOL, that's devious. And a little unfair, I mean, who expects pillars to be mimics? This is the sort of thing that makes player suspect everything, which I've had be a huge problem in the past when I actually need them to accept a thing at face value. Once you've made your players paranoid, good luck lulling them back into a (often false) sense of security!

 

[Paul Farquhar]

LOL, that's devious. And a little unfair, I mean, who expects pillars to be mimics? This is the sort of thing that makes player suspect everything, which I've had be a huge problem in the past when I actually need them to accept a thing at face value. Once you've made your players paranoid, good luck lulling them back into a (often false) sense of security!

That one is down to Chis Perkins, not me.

And it's not unfair so long as the DM clearly includes the disguised mimic in the description.

Mimics could be almost anything. Why would they limit themselves to chests, especially as their prey learns to be wary of that form? It's much more common to find a chest painted to look like a mimic than to find a mimic disguised as a chest. Doors are good, as are chairs. It's got to be something the prey is likely to touch.

And any competent adventurer suspects everything. It's a survival trait. If it's not a mimic it might be some other kind of trap.

 

[DEFCON 1]

And any competent adventurer suspects everything. It's a survival trait. If it's not a mimic it might be some other kind of trap.

Exactly. The entire raison d'etre of mimics and animated armor and piercers and rugs of smothering and gargoyles and flying swords etc. is to have "traps" that are creatures. They exist purely for the DM to catch the players unawares and cause a bunch of damage to them before a combat begins.

If you place any of these creatures in obvious positions intentionally not meant to fool the players... then there's no reason to worry about Surprise or anything. None of it matters. Especially considering that a single one of these things is just gonna get whaled on by the party once combat starts. You place a mimic in the form of a chest in the middle of the room... you as the DM are telegraphing to the players "Yep, this is a mimic." And that mimic is meant to be attacked and killed with most likely no damage suffered by the PCs whatsoever (unless they just completely aren't paying attention.) So whether spells can work or not work, whether Surprise can or cannot be gained... it's all unnecessary concern.

The players did the most obvious math problem and they solved it with no issue whatsoever. Give them their win and stop worrying about it.

 

[Maxperson]

The DM determines who might be surprised. If neither side tries to be stealthy, they automatically notice each other.

-Core Rules​

The mimic is not trying to stealth, therefore there is no surprise round. Everyone takes there turn as normal. However, the PCs may not be aware of what they are fighting, and therefore not know what to target. Example below. If the players touch the mimic before combat starts, then they make a save against being stuck - this does not require an initiative roll, it happens outside of combat.

Here I'm going to depart from our agreeing on things.

There are two things which affect what you quoted above.

First, "Any character or monster that doesn't notice a threat is surprised at the start of the encounter." If there were no suspicion of the chest, regardless of stealth or not, the group would not notice the threat and would be surprised. The stealth checks are made to see if a side is aware or not. In the case of the Mimic, most of the time the party is just going to be unaware regardless.

Second, specific beats general. Mimics have an ability that specifically makes it indistinguishable from a normal object. This ability supersedes the normal stealth rules to determine surprise and automatically make it an undetected threat unless extraordinary means are used, such as the Cleric was attempting and/or being suspicious of it for other reasons.

So baring something extraordinary, there will be a surprise round.

 

[iserith]

Maxperson quotes rules to support a ruling then calls it a "surprise round."

 

[Maxperson]

LOL, that's devious. And a little unfair, I mean, who expects pillars to be mimics? This is the sort of thing that makes player suspect everything, which I've had be a huge problem in the past when I actually need them to accept a thing at face value. Once you've made your players paranoid, good luck lulling them back into a (often false) sense of security!

As I mentioned upthread, that paranoia doesn't usually last long. The group becomes bored of checking every little thing and starts being reckless again. Checking everything takes a huge amount of time and not much gets done during the session.