One of the cool things 3E brought to the table was CR. I’m glad it made it into 5E. Yes, I’m absolutely aware it’s not a perfect system. That said, it does help to balance an encounter, especially for new DMs. When you’re just starting out, it’s hard to tell how many goblins it’ll take to make a good encounter vs how many will result in an unavoidable TPK. It’s far from exact, but at least it’s something.
Now that the praise is out of the way, let’s talk about how to ignore CR.
“Wait, what? Didn’t you just say how good it is?”
Don’t sass me. I’ll explain.
The prevalent idea now a-days is that every encounter should be balanced. D&D is a combat focused game, so it’s important that every encounter be just the right level of challenge. You don’t want something too big too soon- the PCs might die! But, like… what if you do want to introduce a Tarrasque at level 1?
It’s a case of knowing the rules so you can break the rules. Every encounter doesn’t have to result in a fight with the PCs vs the monsters to the death. Honestly, it’s a little boring if they do. What if they have to bargain with an ogre? What if they end up helping goblins? If they fall into a routine of “see monster, kill monster”, it’ll be tough to break them out of it. If you’re going to make unbalanced encounters, however, there are some things worth keeping in mind.
Throwing a monster that’s way out of the PCs league at them can be a lot of fun! In older editions, you got experience points mostly form treasure. Out smarting monsters who were a lot tougher than you was par for course. It’s not as common currently, so it’s smart to do it with care (especially with newer players.) My biggest piece of advice is telegraph, telegraph, telegraph.
Show how tough the monster is. Have it lay waste to a building or easily kill a monster the PCs know to be hard. Leave a trail of destruction leading up to it’s discovery. Have an NPC explain in no uncertain terms how dangerous it is. When all else fails, don’t be afraid to be explicit! Straight up tell the players it’s CR or explain to them that it’s very unlikely they’ll be able to defeat it. The fun in these situations is finding out what the players do to deal with the monster- it’s not about a “gotcha” moment that leaves everyone dead and angry. I’m not saying PC death is necessarily bad, but I am saying its 1000 times better when everything is understood up front.
Try throwing a dragon at your first level players next time you run a game. Watch as they come up with clever ideas about how to run and hide. Give them some tough decisions about who and what to save before the dragon fire comes. Don’t hold back- let them know what actions might result in death, for themselves or others. That dragon will be much more meaningful once they’re strong enough to face it.