Others have mentioned other reasons, but here's another that I find particularly compelling.
In a game of D&D, it is generally accepted that the DM will build combat encounters to be difficult for the characters no matter what level they are at. This can lead to a pattern where your players feel as though, even with all the new powers they are getting, ...
The players may have gotten out of the boss fight I had intended
Excellent - I love it when players outsmart me, giving players the chance to feel clever and empowered is what being a DM is all about.
Victorious warriors win first and then go to war, while defeated warriors go to war first and then seek to win.
Take a step back and ask: what is ...
Play the monster like the ambush predator it is
If a monster is slow and has no ranged attacks, then it is most likely an ambush predator that relies on the element of surprise to catch its prey. This seems to be the case for a chuul, which has many abilities well-suited to ambushing adventurers: it can sense magic (including the magic items that ...
Talk to the DM
Give non-accusatory feedback
Express your point of view using neutral language and I statements. E.g. "When the encounter with 9 ogres ended in the death of all the characters, I felt helpless and it was not fun for me."
Ask for feedback.
Ask them if there were alternative endings they had in mind. It can take a while to get in sync with ...
at the same time I have a hard time understanding exactly what else they would do.
That is the core of your problem. To make them interesting, or boring but "alive" you must understand why they are doing whatever it is they are doing.
4 goblins ambushing caravan may have many different motivations. From the top of my head:
Hungry families they need to ...
CR and Encounter Building are not an exact science
If you find that your group is too effective (or too ineffective) in dealing with enemies, you will have to improvise and adjust the difficulty.
Homogeneous groups share weaknesses
Shambling Mounds lack ranged attacks and are slow. A single character able to attack at range can defeat any amount of ...
Absent Extenuating Circumstances, Yes
According to Kobold Fight Club, which gets its information from the DMG, a party of two level 4 characters would consider 250xp worth of monsters Easy, 500xp Medium, 750xp Hard, and 1000xp Deadly. Furthermore, they should not encounter more than 3400xp worth of monsters in a single day (between Long Rests).
A CR 12 ...
Build a criminal network as your BBEG
I have had success over the years in using the Organized Crime family model (an example is mentioned here) to provide scalable challenges to parties of good, neutral, and evil/chaotic alignments. The emphasis is on rivalry as the tension builder between your PCs and their nemesis.
What are the advantages of doing ...
Group Checks, Success with a Cost, and Skill Challenges
These three concepts are meant to be used in tandem, but can be cherry picked to suit your style of play. I have the most experience using them together.
This is pretty simple. Half the group has to pass at doing some thing. In the examples you provided, this represents the party ...
Combat as a mechanical resource
If you are using XP progression (which is the default way to play, according to the PHB) and you want to give your player characters some catching-up, then you could use an easy combat encounter for this purpose. Similarly, you could give the party items as a reward from such encounters.
Combat as a pacing tool
Carcer and I can independently verify that all your math checks out.
That said, take a deep breath. I doubt this question was prompted by your lack of faith in your own math and reading skills, but instead by your DM's insistence that this encounter wasn't deadly, and this much bold formatting and all-caps in a question (prior to style edits at least) makes ...
Don't give them a villain. Give them an antagonist.
When we create stories about heroes (such as typical characters in Dungeons & Dragons), we often assume that the story must include some evil character as a source of conflict. But this is not universally true. You don't need to design an enemy NPC who is "more evil" than the PCs; in a game with evil ...
Add allies that move, fly, or have ranged attacks
Your players employed good tactics to deal with a particular challenge. Using ranged attacks is such a great advantage in combat that in real life, ranged weapons keep on getting better over the years.
Since you want to challenge your players, you as the DM need to set up a situation that forces them to ...
Try adding warnings and incremental degrees of deadliness to your environmental hazards.
Instead of a single failure leading to instant death, give your players chances to realize the danger and deal with it. Giving your players more chances and information makes them responsible for their potential deaths instead of you.
In the example of the rickety ...
A fantastic source of inspiration for adding flavour and depth to enemies would be the Monster Manual's description of the monsters you are using. There is a lot of content in there besides the stat blocks! Consider what it has to say about Goblins:
They can't help but celebrate when they have the upper hand
They are undisciplined
They are greedy and ...
Because it's fun
The purpose of the game isn't to accumulate, track and expend resources, it's to enjoy the process. Combat encounters are a major part of the major (though not all!) RPG game system designs because many people like to play combat encounters. For example, one can think of D&D 4E as a foray towards 'tactical combat boardgame', which is an ...
There are a number of answers:
I speak as a current player of a 5e warlock, who has 20 cha and agonizing blast, and who does not at all feel like an overwhelmingly dominant force on the battlefield. I manage to do my part, but "trivialize" would not describe.
Melee troops getting up close and personal with the warlock. If you're standing next to an enemy,...
You don't have to use everything that you prepare
It's been my experience that it is much easier to leave something out than it is to make something up on the spot, so my advice is to, for lack of a better word, "over-prepare" in this particular scenario.
That is, build your encounter as if you're planning a TPK, keep that material on hand, and then leave ...
Evil doesn't necessarily get along with Evil.
Your players want to take over the world. Okay. That means that anyone they recruit is going to have to be okay with the idea of the players taking over the world. A lot of evil types out there won't be okay with this. Some of them might wish to destroy the world, some of them might wish to slaughter all ...
If you've got a group that are using creative combat solutions you are going to need to do the same thing to challenge them.
In general, a slow melee monster needs to contain or immobilise faster opponents. So you want to think about setups that trap or corner the players with the monster. How that is set up will be completely dependent on the situation.
At level 2 (on average).
CR tells you the upper maximum difficulty of the monster, assuming a party of 4.
Since the Mimic has CR2, it's a challenge for a level 2 party.
That being said, you can easily adapt this.
After a boss fight, the level 3 party is low on resources, and finding a mimic instead of loot can be a challenge for them.
"Adjusted XP" is for determining encounter difficulty; actual XP is what you give to the party for beating the encounter
The difference between XP and adjusted XP in determining the difficulty of a combat encounter is explained in the guidelines on building combat encounters on Basic Rules p. 165 or in the corresponding section on DMG p. 82.
Step 1 and 2 ...
My idea is that there is a hidden pirate witch on board that can get a lightning bird to attack once a day, or something, but that she needs to burn incense as a consumable part of the spell.
This is actually exactly just what you need already. Monsters and adversaries in 5E do not need to follow exactly the same rules as PCs, and in fact in many cases ...
You were just over "1 day's XP budget" (five minute adventure day)
In the Basic Rules p. 166/DMG p. 84, there's another table that lays out the estimated "adjusted XP" for an entire adventure day. For your party: 7th /5,000/ x 4 = 20,000. (Your adjusted XP calculation was correct at 23,400).
The usual adventure day is designed with "6-8 encounters of ...
It's good that your players are using tactics, just remember you can as well. Players will always try to fight safely so it helps to design encounters that make that less attractive.
You have lots of options for keeping fights close.
Ambush: predators and villains want ambushes so have them set up for them. Spider webs, burrows, camouflage, there are ...
There are two reasons I use those now and again
Sometimes, the players need to feel successful.
I use this particularly with new players, and with younger players when I deem that a tougher encounter might go badly.
Sometimes, the party's foes make a mistake.
Just as the PCs can now and again underestimate how hard an encounter or monster is, the ...
Not for the Beast Master Companion
The beast companion for that Ranger is granted by their class features. This makes it for all intents and purposes part of the Ranger (and included in their levels, as it were). In particular it uses their initiative and their actions to make attacks, meaning they are not an independent creature contributing to encounters. ...
He does have Wish, but maybe one of the following either has happened or will happen:1. He's cast it once, but now he's unable to ever cast it again. From the spell's description:
Finally, there is a 33 percent chance that you are unable to cast wish
2. The spells fails, anytime he casts it.
The GM has great latitude in ruling what ...
I have this exact issue in a game I'm running (and the warlock can now fly, making him even more effective!). My strategies are still evolving, but I broadly have two categories I use to provide challenges for him: hard counters and soft counters.
Of those, I strongly prefer the soft counters.
Soft counters are anything which frustrates or ...