New DM on House Rules, concerning Nat20 & Rule of Cool

Question

As a DM making a house rule, am I allowed to grant "Rule of Cool" to Natural 20 rolls in exchange of giving "Rule of Uncool" effects for Natural One rolls? (but all within the boundaries of RAW as well).

• In battle, a small PC rolling Nat20 successfully maneuvers himself and climb on the back of the big bad creature (Legolas Style), only to roll Natural 1 in his attack and accidentally hit his allies.

• Failing Deception on guard with Nat1 roll additional 2 arrives and a High Ranking Knight, only to roll Nat20 and convinced the High Ranking Knight instead literally allowing you to pass the area with no consequence at all.

I just want to encourage imagination by introducing some Matrix dodges and Epic fails in the game that is somewhat lighthearted and funny especially to noobs like me.

Am I being a bad example of being a DM? Should I discontinue this approach?

Answer 1

Natural 1s and natural 20s are poor triggers for anything termed “Rule of Cool.”

The issue is that they are purely random. They don’t happen when it would be cool—they happen randomly. How “cool” can you make a crit against random goblin #813?

This also ties into the inherent problem of crits and fumbles—they are bad for PCs. See this question for the “v.3.5 revised edition” of D&D—everything in it is still true here. If a PC gets a crit, they are probably critting orc #125; if an NPC gets a crit, it’s all-but-guaranteed to be against a PC. Fumbles work the same way; every time “team PC” fumbles, it’s a PC doing it, but when “team monster” fumbles, it’s probably some random mook. Therefore, every crit against the PCs, or fumble by a PC, is definitely going to involve someone important. The reverse will rarely be true.

Intra-party inconsistencies are also a problem: if the fighter attacks four times, the rogue attacks just once, and the wizard only casts a spell that doesn’t even use an attack roll, the fighter is 4× as likely to fumble as the rogue, despite being the “superior” fighter, and the wizard isn’t at risk at all. That’s not great.

And on top of that, even when a crit or fumble does happen with an important NPC—say, the BBEG—it still tends to not lead to a lot of “cool,” because it can cut short what should have been a cool, challenging, cinematic fight in a rather anticlimactic way. And if that happens once, maybe it’s a funny story, but if it keeps happening, it dilutes the effect and tends to be far less interesting.

So for all of these reasons, such “extra effects” on nat-1 and nat-20 are a bad idea.

Instead, “rule of cool” effects should be a matter of judgment and taste—and dice don’t have those. You need a person for those. Luckily, D&D’s got one—that’s you, the DM! You can use dice rolls to guide you—maybe you only consider applying some “rule of cool” effect when the die roll is very good, or some “rule of uncool” effect when the die roll is poor, but you remain in control. You can decide that missing is problematic enough and doesn’t need to be compounded. You can decide that an 18 is good enough in the right situation for some cool extra to happen. You can listen to a player’s plan, and decide it’s so awesome that you say, “you know what, that just works, just this time, because that’s awesome,” and not even bother with a die roll. And another time, you can hear the players talking the dumb barbarian out of a dumb plan, and say “you know, that sounds pretty in-character for you; I think you’d do it, and it’s gonna go terribly. I’ll give you Inspiration if you just go with it and let it fail.” And Inspiration can serve pretty well as “currency” for getting Rule of Cool effects, which allows for a back-and-forth where sometimes things are awesome and sometimes things aren’t working and the players have to figure out how to be awesome anyway.

But the key is you know when something is cool. The dice don’t.

Answer 2

I think your question as it stands requires a certain amount of opinion (which tends to get frowned upon in these forums), but think it's still worth an answer to clarify some RAW and point out some pros and cons for "rule of cool/uncool" natural 1 & 20 house rules.

First, natural 1s and 20s as "critical misses" and "critical hits" only apply to attack rolls. There is no such rule governing ability checks.

This is important because even a natural 1 on an ability check could end up as a semi-reasonable result once all modifiers are added in. A 20-Charisma bard with expertise in Deception could still get higher than 10 on a natural 1! It may not succeed, but it's not a disastrous failure either.

Second, be aware of accidentally introducing unfairness into any nat1/20 rules - a common criticism of such things as critical miss tables and similar.

For example, let's say you rule that a natural 1 causes a weapon to break or an ally to be hit. Now, as a fighter levels up they get more attacks a round representing the fact that they are improving. Except when that happens they have more chances to roll a natural 1 and more chance of their weapon breaking or hitting an ally. Not to mention this rule would unfairly punish weapon-users over magic-users and possibly favour some PCs over others.

Having said all of that, rule of cool and uncool can be fun as long as all your players are on-board. It can add dramatic flair and be funny - just be wary of attaching rules-based mechanical effects to such situations.

(In your example, a natural 20 on a Deception check causing a high-ranking knight to allow the PCs to pass by without question is a perfectly reasonable use of such a skill!)

Answer 3

This is something to talk about at the table

There is no One Way to do this. There are pros and cons and concerns that should be discussed at the table and everyone should be on board with whatever is decided.

Attacks

I've played at tables with critical fumbles and critical passes. I'll explain our system and then continue with table response.

Our critical fumble was based off of a d100. Scale of failure is based on the die roll, with a 100 being immediate death.

In general, the table liked and enjoyed this. I wasn't a big fan and it changed how I played the game. As a paladin, an increase in the number of my attacks meant an increase in the risk of failure. This generally meant that I almost always waited to position myself for advantage to minimize my risk of death of Ability Score loss (yes, the latter happened to me, almost permanently until level 20.) It made games stressful and not fun for me - and even influenced me to try and design my next character to use more saving throws instead of attack rolls. That decision tree shouldn't be there in my opinion.

The failures can be fun, but really only if everyone is on board. I wasn't, but I dealt with it. This is really going to be up to every table to determine what is fun for them and what penalties keep it fun.

Additionally, critical fumbles can be worse than critical hits - and that's a real concern. I would look at comparing the worst fumble vs critical damage opportunity to determine what's equivalent if you go through with this. An extra few HP of damage I don't think is equivalent to major problems for a player.

I personally prefer no critical fumbles, or just narrate something fun without a mechanical consequence. I have recently thought that because I often let players narrate critical hits, they should narrate their critical misses, too.

Ability Checks

This is a bit trickier. I typically am of the belief that a natural 20 is not an automatic ability check success. I'll set a DC if the task is doable, but if it's impossible, then no roll can happen.

This is a pretty important piece of detail here. Just because a player wants to do something, doesn't mean that it's possible. It doesn't mean its impossible, but it is up to you and the player to talk about what they're trying to do and explain why it wouldn't be possible if you don't want the 5% auto success odds (assuming no advantage.)

The table with the critical attacks also used critical successes and failures. The failure didn't 'do' anything, but a 1 resulted in a failed attempt no matter what (or no matter what your modifiers are.) This also felt frustrating because I didn't feel the game wanted it run like that. It turned something that generally could still work to something that guaranteed a failure and that felt less than satisfying.

But again, come up with a system that works for you and your players? Do you and they want every action to possibly succeed? Does everyone understand the penalties for failure? Is this fun for everyone?

General Narration

And remember that every action can be narrated. They can be narrated as awesomely or as mundanely as someone wants - you don't need criticals to do that. Have fun with descriptions, that's a great way for people to get more into their characters and their actions (if that's what they like.)

Answer 4

Rule of Cool is always worth considering

When it comes to the rule of cool approach, there's really no harm in deciding to interpret a critical roll as something really cool. This could be anything from giving some sort of bonus discovery when doing a perception/investigation check to search a location, to managing to knock out a mook when trying to grapple them.

Letting the dice inspire the cool moments can help to enhance the feeling that there's more to what happens than mere PC decision - luck plays a role in events, too. This doesn't mean that every nat 20 must become a cool moment, but that a nat 20 should be an additional prompt to ask "can this moment be made more cool?"

This is the way that one of my DMs likes to run it. Natural 20s get rewarded if he can see a cool bonus effect quickly. If you're rolling to remember a mundane piece of information, it's not likely to get a rule of cool bonus... but if you're trying to knock down a door with athletics, you might manage to do it at just the right time to knock an enemy over behind the door.

It's important that this doesn't become a requirement for "rule of cool" being invoked - it should only ever be a catalyst, something that reminds you to consider the rule of cool.

Rule of Uncool must be very carefully used

When people play D&D, they generally want things to feel cool. Critical fails can sometimes contribute to it feeling cool. But if every natural 1 means that you hurt yourself or an ally, for example, it will become tiresome very quickly, for most tables.

Instead, think of it as a "Rule of Funny" moment. A natural 1 on a perception check to look for enemies might see you watching a squirrel dart through the forest instead. A natural 1 on an athletics check to bust through a door might see you fall on your butt (harmlessly, but feeling quite embarrassed).

Players should never feel like they shouldn't try things because "what if I roll a natural 1?" - a 5% chance of something actively harmful or problematic isn't most people's idea of fun.

It can be quite funny, sometimes, for a rule of funny to be a rule of uncool. A player tries to demonstrate their skill with a knife by juggling, rolls a natural 1, and cuts their hand for 1d4 slashing damage... that's funny and uncool. A player tries to attack an enemy, rolls a natural 1, and breaks their weapon... that's not funny, and unless it's meant to be a feature of the weapon, or of the enemy, it feels like you're being punished for one of the fundamental parts of D&D.

As others have said, it comes down to what the table thinks falls within cool/funny. If the players (including the fighter) find the idea of a natural 1 causing the fighter to drop their weapon to be funny, then do it. If the fighter is going to feel like they're being punished for fighting, then don't... most of the time.

It can always be funny to have it happen once, in a controlled context. The Level 9 fighter tries to strike down a simple goblin after the goblin says something that offends her, rolls a nat 1, and manages to fumble the weapon, which the goblin grabs, leading to a chase to reclaim the weapon? That can be hilarious... once. If it happens on every nat 1, it's just not funny anymore. Especially when, at high levels, the fighter ends up with an 18.5% chance of it happening at least once, on EACH turn. In 1 minute of fighting, it would happen at least once more than 70% of the time.

Answer 5

While it's not in my personal style to put a Rule of Cool on every Nat 20, this isn't an overly bad practice. It adds drama when a nat 1 occurs and adds theatric relief when a nat 20 occurs. The only issue I see is on some crit fails when you say other allies are hit. Unless other players are okay with it you should avoid ruling that other PCs are accidentally wounded just due to bad luck.