So, recently, I had an issue where I had to make a call on a custom-made weapon, and I'm not sure I handled it very well. The player was using a human alchemist, and instead of throwing 'bombs' every turn, he came to me with a concept for a weapon. Basically, it's a bunch of vials of acid, alchemist fire, and the like, wrapped up together in a fine-mesh net, attached to a staff with rope, and wielded in a similar fashion to a mace.

My response: if you take the appropriate penalties for wielding it, then you can use it. It came out to something like a -6 on attack roles (-4 for non-proficient, -2 for using what amounted to a large-sized mace). However, as he stated, so long as it actually struck the target the glass vials would break and deal damage, so he had to hit against their touch AC.

I thought the idea was impressive, and didn't think it would actually be a huge problem for an enemy... until it was. He ended up tossing something like 200 vials in the net, and managed to kill something a full 10 CR higher than the group, on his first turn.

Well, as you can guess, he's not allowed to use that item anymore. However, I really enjoy seeing players put the effort into this kind of creativity, and I would hate to discourage it just because their end-goal is to make something broken. (After all, if it wasn't beneficial to them in some way, why put in the extra effort?)

So, how do I handle situations like this? How do I reward him for his inventiveness, while not allowing him to break the game? Advice on this specific situation would be appreciated, but mainly I'm looking for a way to handle the issue as a whole. Any experience with the same problem is welcome, of course.

  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$
    – mxyzplk
    Commented Feb 6, 2017 at 13:16

7 Answers 7


Encouraging inventiveness is easy. You've already done it, in fact: You simply have to reward it by allowing it to (occasionally) succeed.

Avoiding breaking the game is also easy: You simply disallow anything that lets players to bypass the obstacles presented by the game with less effort than it would take to tackle those obstacles in a more traditional way.

Obviously, these two goals are hard to reconcile, but I can suggest a few things that might help.

First, let your players have the benefit of their invention, but remember to account for the costs: In your example, your alchemist has developed a devastating weapon, but one which eats through very expensive ammunition at a disturbingly rapid rate. Once the disparity between party member wealth levels grows a bit, he might start to worry. Also, given that it is a devastating weapon, even if it is expensive, ask yourself why other people don't use it. I imagine it would take just one orc with the Improved Sunder feat to make your player realise that there are pitfalls involved in waving acid vials over his own head.

Second, remember to include at least a few situations in which the invention does not work, to keep your players on their toes (and encourage future inventions): There's no end of creatures immune to acid and fire, so let them crop up occasionally - and your alchemist would be in strife if away from civilisation for an extended period.

Finally, don't be afraid to condtradict previous rulings if you can come up with a good reason for it. Yes, you should avoid it most of the time, but inventions are a special case, since by definition they're trying something new and unknown: Invention is inextricably paired with discovery. Be tactful, and start by saying "There's something I didn't think of that's kind of relevant to that idea you came up with," but be firm, and try and provide a reasonable in-game justification for it. "Your acid net? The ropes that make it up only have about two hit points, so it should be disintegrating every time you use it. Also, how have you been protecting yourself from the splash?"

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    \$\begingroup\$ Does he carry spare vials to reload his weapon? What happens when someone hits him, or worse yet, shoves hit into a wall? \$\endgroup\$ Commented Nov 21, 2012 at 6:50
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    \$\begingroup\$ @Hand-E-Food Honestly, I'm just hoping he doesn't get the idea to load a catapult full of the stuff. Same concept, except much more versatile use, with the main drawback being the need to lug around a catapult. \$\endgroup\$
    – Zach
    Commented Nov 21, 2012 at 8:46
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    \$\begingroup\$ The force of the throw would likely crush the vials before they left the machine. \$\endgroup\$
    – ikegami
    Commented Feb 5, 2017 at 23:22

Basically, it's a bunch of vials of acid, alchemist fire, and the like, wrapped up together in a fine-mesh net, attached to a staff with rope, and wielded in a similar fashion to a mace.

Spoony, from the Counter Monkey blog series, mentions Alchemist's Fire every now and then. It's great, and everyone thinks it's great, but here's the thing: eventually, you're going to roll a 1. Eventually, the party's pyromaniac is going to set someone next to them on fire, and then be lit on fire themselves, if they didn't do that to begin with. And then what happens when the person loaded up with alchemist's fire is on fire? They explode. And who's right next to them? The entire party.

Someone swinging around 20 vials of alchemist's fire on a pole is no better.

Wield chemicals with extreme caution

So, how do I handle situations like this? How do I reward him for his inventiveness, while not allowing him to break the game? Advice on this specific situation would be appreciated, but mainly I'm looking for a way to handle the issue as a whole. Any experience with the same problem is welcome, of course.

Here's how you do it: let him use it. The pyromaniac is carrying around at least 200 vials of acid, alchemist's fire and other dangerous and possibly volatile chemicals, since you said he managed to use all those in one blow in one encounter. All of those containers are weak enough they'll shatter if smashed into someone. That's a problem.

  • What if someone runs up to the pyromaniac, swings a club, and smashes his backpack - the one full of vials of acid and alchemist's fire - whilst he's wearing it? Oh, the club didn't pass his AC? That means he either dodged it or his armor blocked it - maybe his backpack stopped the blow.

  • What if the character misses with the weapon, and the chemicals swing around to smash against the shaft itself? What if, even after normal use, the staff has acid trickling down it?

  • What about the day he rolls a 1 - which will happen one day - and swings the mace into an ally within the weapon's reach? What if he swings it back and smashes it on the wall behind himself?

  • What if, even out of battle, he trips over, falls, and smashes his hundreds of vials of chemicals? What if he fails a climbing check, or tumbles after a dodgy jump check?

  • Even if he hits, those chemicals are going to splash. On other people.

Pyromaniacs have a short life expectancy, and so do the people who travel with one. If your player wants to walk around with dozens of vials of every dangerous chemical he can think of, he and his party should be aware of the dangers.

Because this is a dangerous situation, you should talk to your players in advance about what should happen when the user of the weapon hits, misses, or rolls a dreaded 1. That way, when 20 vials of alchemist's fire and acid one day explode above the pyromaniac's head and leave no recognisable remains after a roll of 1, they won't be annoyed that it was a GM fiat - everyone knew that if a 1 was rolled, that was one of the possible outcomes. The rest of the party will just be relieved it wasn't one of them getting hit.

Target his weaknesses

So: your pyromaniac has thought ahead and has fire and acid resistance - from resist energy, I assume. His party members might still be entirely vulnerable - but let's assume they're protected too (via communal resist energy - which would only last a few minutes).

Even with protection, your pyromaniac and his weapon is still quite vulnerable. I suggest you take advantage of it.

The first vulnerability is that resist energy can only resist so much damage, so unless his caster level is high enough to exceed the damage cap for the weapon, he and his allies can still take damage from a disastrous swing.

The second, and greater one, is his enemies' ingenuity. No doubt word would spread about such a fearsome and eccentric weapon. Any organised group of enemies should begin strategising how to weaken him. At this point, you've reached the situation a lot of new weapons create: an arms war, with one side inventing weaponry, and the other working out how to counter it or make it work against its wielder. Here's some potential strategies for countering his weapon:

  • Target his weapon when it's loaded. Arrows and rocks (from a sling or hand) can smash those vials before they see any proper use. Best case scenario: target it whilst the end loaded with vials is over a party member's head, or right near someone.
  • Target his bag of holding. Find a way to puncture, slash, or burn a hole in it. Even if he protects it, it must be vulnerable when he's loading his weapon.
  • Force him to pop his resist energy ahead of time, so that he can't use it when he wants to use his weapon. Then bombard him with energy he's not resisting: electricity, cold or sonic damage. After he's used it up, and resist energy's effects have ended, ambush him with fire.
  • Don't let him swing the weapon safely. Don't give him enough room, and have enemies readied with a chain to trip him in mid-swing, or a bow or sling to smash the weapon.

If your players aren't up against any enemies with the organisation or ingenuity required to engage in this arms war, then either make the enemies begin to get organised or introduce organised or clever enemies. Either that, or forfeit the arms war and leave enemies with no recourse against a devastating weapon - or disallow the weapon.

Ultimately the goal is to keep things in line

If your character invents a powerful weapon, make it come with a cost. Luckily, a pyromaniac's weapons generally come with an inherent cost. If he works out a way around those costs (as he has), make the weapon difficult to use effectively, instead of subjecting helpless enemies to a super-weapon.

The point of all this is to just keep the reward and the risk or cost in proportion. The point is also to prevent your party from wielding a super-weapon nobody can defend against.

All these actions work under the assumption you allow the weapon at all, and ruling it out is certainly a simpler option, but that won't encourage ingenuity (something I love to encourage in my own games).


Before approving weapons, check your math. While a player can certainly assert that he can swing it, it's useful to double-check.

One swing of this 200 pound weapon* (well, probably a bit more because the stick weighs something) Costs him 20*200 gp, give or take. 4000 gp in one shot buys an awful lot of damage.

It's not that it's overpowered, it's that it's too light. Spending 4000 gp on a swing is not a particularly efficient use of money. There are magical options that can be far far more deadly (consider, a command-word activated magic missle widget.... duct taped to 100 others...)

On the other hand, if they're willing to drop 4000gp on a touch attack, let them. It's far better for them to waste their money this way then on an almost completely free scroll case filled with hundreds of scraps of paper with "I prepared explosive runes" today inside and a lovely shatter (or dispel) spell.

* Quoth the pfsrd:

Alchemist's Fire: 20 gp 1 lb.

  • \$\begingroup\$ At the time, he was using acid, which cost ten gold per. He said that he made the stuff himself (which, having the feats and bonuses necessary, I allowed him to), so he was able to 'buy' 300 of them, for 1k gold. So, for the cost-equivalent of a +1 armor enchantment, he was able to buy 1 1/2 uses, at his current rate... except, since 50 vials alone would be able to kill most things, it's more like 6 uses. \$\endgroup\$
    – Zach
    Commented Nov 21, 2012 at 8:41
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    \$\begingroup\$ I might be missing something, but in my opinion, damage from multiple vials shouldn't sum indefinitely, it should never be possible to exceed the rules for being fully immersed - d20srd.org/srd/environment.htm#acidEffects, that is 10d6 \$\endgroup\$
    – Maurycy
    Commented Nov 21, 2012 at 10:27
  • \$\begingroup\$ Eh. There are easier problems then debating intended damage. \$\endgroup\$ Commented Nov 21, 2012 at 10:36
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    \$\begingroup\$ I dunno. I think Maurycy has a great point. You can't get more covered in acid than being completely immersed. If the damage for that is determined to be 10d6 (presumably because that's how much surface area can maximally be exposed), then it makes perfect sense to say, okay, that's the maximum that one can possibly deal from acid damage from the swing. Great, logical solution. \$\endgroup\$
    – Beska
    Commented Nov 21, 2012 at 14:43

So your player has created an uber-weapon. Other answerers have given good technical/tactical suggestions. Capping the max damage makes sense - only so much acid can have an "effect" given the limited surface area, splashing, and so forth. Adding risk of collateral damage or accidents adds a chance for some painful hilarity, however this must be used sparingly else it causes excessive annoyance. The expensiveness of the weapon 'charges' is interesting however depending on your party's income it may or may not be effective as a balance.

But heck with all that. Why bother trying to balance it, when you can have fun with it!

What materials does the alchemist require to make the acid? Perhaps some key ingredient is in limited supply, and he quickly depletes the local supply. You drop a rumor of an alternate source, but... And then you attach your stereotypical 'fetch' adventure. A vein of mineral spied out in a nearby cavern. Or a caravan transporting the last of it to a distant king. Or a foul-blooded dragon in a fetid swamp.

If the weapon really is so great, well of course word gets around. Another alchemist, who has been attempting for years to develop "basically" the same thing becomes irrationally jealous and obsessed with monopolizing the claim to fame. Problem is, he understands the inherent weaknesses of the player's weapon design and enjoys nothing so much as exploiting a flaw...

Perhaps also one's ordinary foes will adapt to the new weaponry. They'll learn of oils that make them more resistive to acids, or powders that help neutralize it. They'll learn to target the alchemist's weapon first. And so on. Adapt or die.

Others may figure out the design of the weapon (or sneakily buy or steal the design from the players themselves). Suddenly the players are faced with enemies bearing the same terrible weapon...

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    \$\begingroup\$ +1 for simultaneously rewarding players for creativity and limiting the effectiveness of their ideas by making them the basis for stories. \$\endgroup\$
    – GMJoe
    Commented Nov 22, 2012 at 4:01

One way to balance player inventions that hasn't been mentioned yet is to compare them to spells of the appropriate level.

For example, at level 7, players have access to level 4 spells. The highest damage single target level 4 is probably Finger of Death, which deals 10 damage per caster level, or 70 damage on a failed save. Several other spells deal something on the scale of 1d6 damage per level. Comparing vial damage to this says that allowing about 7 or 8 vials in one strike is probably reasonable, damage-wise. This is cheaper than a 4th level spell scroll, not as powerful in the non-damaging aspects, but can be made and used by non-casters.

If you want to tie the maximum damage to something in-game rather than an abstraction like level, let the player load the weapon with a number of vials based on an appropriate skill.

For example, maybe they can make a DC 10 Alchemy or Knowledge(Engineering) check, and load 2 vials into the net plus 2 for every 5 points they pass the check. This way, they get more value as they gain levels, keeping it (somewhat) in line with other damaging effects.


I know little of Pathfinder, so if my 3.5 translation there is a bit rusty please forgive it.

So, how do I handle situations like this? How do I reward him for his inventiveness, while not allowing him to break the game?

When approving a weapon, make sure to compare it to others. I like my hand-and-a-half sword of 1d10 with a 19-20/*2 crit, as well as my one-handed sword of 1d8 with the same crit, but I could always switch to my light weapon of 1d6 which has the same crit. Or better yet, there's something one-handed for 1d8 with a 20/*3 crit. But they're all balanced against each other. Even a scythe in the hands of a weapon specialist will still only top out at so much damage. Ruining something of that high above the party level means something may have gone amiss in the calculation, because as GMJoe pointed out in the comments even total immersion is usually only ten dice of damage.

My second recommendation is to test the weapon under it's worst case (for the DM) scenario before approving it. Let's say you didn't like a scythe dealing 2d4/*4 with two hands and you wanted to have a greatsword on a stick (ignore the physics here for a sec) that would deal 2d6/19-20/*4. Really strong. See if it can too easily take down something well above their level, or even too easily at their same level. If so, you'll have a hard time balancing that. If not, or if your game is full of creatures resistant to that type of damage like skeletons or what-have-you, then all's fair.

Basically the balance aspect boils down to what a friend of mine says about multilevel marketing schemes - if it works so well, why aren't we all using it? If a PC has the shishkebab from Fallout Three, then why are the king's guards bothering with their boring enchanted-but-not-otherwise-special longswords?


I think that you've definitely encouraged your players' inventiveness, so no trouble there. However, you should also try to limit how far it goes. I think you've recognised this yourself, which is why you're asking this question.

To encourage inventiveness, let it give players an edge. Don't let them build something game-breaking, let them invent something that effectively levels them up, and increase the encounter difficulty as well. The key is managing expectations. If players expect to be able to build a one-shot kill device, then it's because you've not indicated strongly enough that they can't. Sorry, but that's how it is as a DM.

If your players are able to increase their effectiveness, even by a small amount, by being clever (e.g. "I cast Continual Light on a slingstone to blind any infra/darkvision-users for one turn when I sling it at them" is suitable, while "I cast symbol of insanity on a bouncy ball to hit every opponent at the same time with it when I throw it" is NOT) and get used to this being how far they can go, they will probably start thinking in the right ballpark.

Players going too far, like in your example, can be stopped in three main ways, in my experience:

  1. They can have gruesome consequences for failure outlined. A PC will generally try to not die, which is why they try to get an edge in combat. If their new toy is more likely to kill them than the goblins, they'll tend to drop it like a hot rock. Alternatively, the risk they take while using their special weapon can increase over time (maybe their enemies figure out a way to neutralise it or make it backfire - in your example, shoot a volley of burning arrows at the Alchemists Fire), so to keep their edge in battle, they'll have to keep inventing.

  2. Players tend to not use a new invention more than once if the enemies start copying it. Using your example, the BBEG (if you have one) might hear about the weapon and decide to buy a few thousand vials himself for the showdown. A lot of enemies might learn to cast magical darkness on a rock and throw it at the PCs if they are regularly blinded by continual light spells. Any ideas you get about how to improve the invention, use them a few sessions later when the players least expect it.

  3. Simply rule that it won't work as intended. For example, your alchemist's weapon could be ruled to simply cause splash damage in a certain radius to stop him essentially running towards someone while holding a live grenade. This combines nicely with the other options. Maybe an enemy can get it to work, maybe the weapon has gruesome consequences for the players instead of the enemies. Basically, make the weapon less effective than the player hoped. Nerf it to what you'll let them get away with. Remember, the stronger a weapon is, the more risky it should be to use.


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