Help! My PCs polymorphed my boss enemy! What do I do?

Question

Our Druid has recently gotten access to the polymorph spell and has started polymorphing the opponents I so lovingly crafted for our (well, mostly my) enjoyment. (So far, he has been turning them into rabbits, not yet killer whales.)

Now, the canonical response to a polymorph is to reduce the polymorphed creature to 0 HPs, upon which it will transform back. Or to attempt to break the spellcaster's concentration.

However, polymorph is a 4th level spell, not a cantrip. It does not seem all that likely the target's allies know the spell, can connect the dots when their friend suddenly turns into a bunny, and start to attack the bunny or the spellcaster. It seems more likely that they will blink upon seeing their friend transformed into a bunny, shrug, write him off, and continue battling the PCs as before, which would essentially take the target out of the fight.

I have been thinking about allowing the target's allies an Arcana check each, against some reasonable DC (e.g., 14, which is 10 plus the spell level of polymorph). On a success, they recall hearing about the Polymorph spell and the two possible remedies. On a failure, they don't. In which case the target will remain polymorphed until it gets hit by a stray fireball or some such. I might even allow the target itself an Arcana check, and on a success, it will try reducing its own HPs. Well, this might at least make for some fun.

It looks to me like polymorph might be a bit overpowered against opponents who no have legendary resistance, and whose allies only consist of non-spellcasters because they will likely not know what steps to take to break the effect. Is there a better way to role-play what happens to a polymorphed enemy?

To address the concern about this being opinion-based: I fear that if adversaries often do not know how to break the polymorph spell, this will make combat more boring, since the PCs will simply open by polymorphing what (they think) is the most dangerous enemy, taking him out of the fight entirely. Also, it's asymmetric, since the PCs know how to deal with someone polymorphing one of them. What techniques could I as the DM use to make sure battles stay interesting, possibly even fun?

Answer 1

According to this answer, anyone who sees a spell being cast can use a reaction to make an Arcana check with a DC of 15+spell level, with advantage if the spell is on your spell list. Success means you identify the spell, which presumably means you also know how to get rid of it.

However, let's think about this. You're in battle, and an enemy spellcaster walks up and waves his hands and shouts some nonsense words, and suddenly your friend turns into a bunny. You probably wouldn't know to kill the bunny, but you'd definitely know that you should break the spellcaster's concentration if you want your friend back!

You've written that you think it would be difficult for the NPCs to figure out which of your party's several spellcasters had cast the polymorph spell, because several of them were all casting spells in the same round. I think you should allow your NPCs to be aware of turns, and to be aware of whose turn it is when a given effect happens. Your player characters are keenly aware of this, so it seems only fair that the NPCs should be aware of it too.

The best response to this is in encounter design. Either (1) don't give the player characters a battle where there's only one important foe, or (2) if you must do that, give the foe some points of legendary resistance, so it doesn't go down so hard when hit with save-or-lose effects.

Answer 2

I don't think this is actually a problem; the game is working as intended. Using the polymorph spell in this way is not overpowered. It's really no more powerful or ruinous to your encounter than any other temporary target removal spell, like resilient sphere, banishment, hypnotic pattern, or various wall spells (in fact it's somewhat less powerful than many of those because the sphere or banish can't be wrecked by a poorly aimed area damage spell). It doesn't allow the players to end the encounter with any less total HP damage; it just splits up the fight by keeping one set of enemies out of the way while they deal with the others.

I mean, sure, it's a good effect; it's a 4th level spell slot with a save, so it ought to have a big impact. But is temporarily removing one target from the fight really "ruining the encounter" more than other effects of similar level? Sure, they're manipulating the action economy, but that same slot could have been an up-cast fireball or lightning bolt, after all. Would you be complaining about it "ruining your lovingly designed encounter" if somebody had rolled up with a fireball and just flattened nearly all the minions in one shot? Or would you be saying "yes, that's how spells work in this game"?

That said, my opinion is definitely that the enemy should be aware of which spellcaster is responsible for which effect. Even if there's five guys all casting magic, there's nothing in the game that says the other side needs to make checks or something to figure out who did what. A round of combat happens in order -- knowing that the druid cast the polymorph spell should be no more difficult than identifying who the fighter hit with his sword or which character threw that fire bolt last turn. Obviously, there's an exception in extenuating circumstances, such as a hidden or invisible spellcaster, but if they aren't going out of their way to conceal who's doing what, it should be at least as obvious as firing a crossbow.

Answer 3

Polymorph can be a very strong spell but there are several strategies to help get around it wrecking your boss fights.

More encounters

Throw more encounters at the PCs before the boss fight. This will force them to burn more resources and therefore they'll be heading into the last fight weaker than they normally would.

Give them another use for that spell

My players have learnt the benefit of using Polymorph on themselves, particularly when one of them gets beaten up quickly and combat healing is limited. So I use that to give them a choice - polymorph the bad guy or one of us?

Legendary Resistances

They're just kind of mandatory after a certain point.

Enemy casters

Dispel Magic and Counterspell are perfectly valid defences to this situation so don't be afraid to add some casters to the minions of the big bad. I've noticed that most players like getting counter spelled as much as they like doing it - it all adds to the excitement.

Get inventive with breaking the spell

The Polymorphed baddie might get caught in an AOE 'accidentally' or attack the PC with Armour of Agathys up... Come up with ways to break the spell beyond making the caster lose concentration.

The monsters know what they're doing

Depending on the level of the PCs and their opponents, knowledge of spells in general might be perfectly acceptable and there is no reason why an NPC can't figure out what happened when they see the Wizard wave their hands and the boss turn into a rabbit. They don't even need to know the particular spell, just that the guy in the pointy hat did something bad.

Answer 4

Let the players have an easy win

It’s a just reward for their foresight in choosing that spell, keeping the spell slot available, and a little bit of luck going their way. They get to feel awesome and that’s sort of the point of D&D.

Answer 5

Your players are not in enough danger. A similar spell exists in most LARP systems, and you can instantly understand if someone is an experienced PLAYER or not by how they use that spell - only beginners use it on enemies. Everyone who has played a bit understands that the spell is much, much more useful on yourself or your allies. (there are other spells in this class as well, like petrify).

They SHOULD reserve Polymorph for use on themselves, to escape from dangerous situations, sneak through narrow openings, fly over a canyon, etc. etc.

If they don't, then clearly you've not given them enough situations in which Polymorph would've been useful and they're sorry that they burnt it on turning some enemy into a rabbit two encounters back. You should start doing that. Give them more situations in which maybe Polymorph isn't the only solution, but it would've been a comfortable, easy or safe option.

Once they understand just how versatile and powerful the spell really is, they'll stop wasting it on temporarily taking out enemies. That's what Sleep is for. :-)

Answer 6

Add more depth to your encounters rather than just meeting the thresholds with calculated CR.

I have DM for 1-5 campaigns, epic one shots and LV15+ campaigns, everything below is from personal experience.

If its a BBEG then why would he just be sitting waiting ?

1. Put a ward of silence on his door so when the party open it there silenced for 1 minute on a failed save, justify this by having the BBEG go straight into a monologue that the silenced players cant interrupt, never underestimate the ego of villains.
2. Obstacles that obstruct the BBEG, why would he be sat in a large empty room when the heroes arrive, if all 5 spell casters have unobstructed casting on turn 1 then BBEG deserves to go down.
3. Defensive spells, why wait to cast mage armour on the BBEG first turn when he could have cast it while you were loudly killing all his minions. Maybe he holding a counter spell for the first spell that targets him, these aren't thr first adventurers he's fought after all, he knows the score.

Not boss encounters

Hordes are so much worse than a dragon, a paladin can crit-smite through 1/3 of a dragons HP before the wizard turns it into a rabbit. 25 goblins with 12 Hp each so the average cantrip cant one-shot them is a problems on every day of the week. Do you slog through them taking the hits or burn resourced to clear the room, either way there's nothing to polymorph. To justify 25 goblins have the hatchery in the dungeon, BBEG need to be getting goblins from somewhere, a dozen children (disadvantage on all attacks), half dozen mothers (immune to charm, fear ect) and the rest generic goblins. An entire graveyard of skeletons works the same way.

Lean into the skid

Players do crazy things because they want to have fun, as much as it feels like there trying to cheat you there not so its not always about trying to counter there tactics so just enjoy the ride.

So your BBEG is now a rabbit, ok, well the badass looking mercenary is not going to defend a rabbit that cant pay, maybe he sheaths his blades bids you good day and just walks out of combat.
Maybe a henchmen grabs the rabbit and tries to escape while the others try to hold you back, the player know they cant just fireball the running henchman in-case they dispel polymorph.

Answer 7

This is a generic problem, because the PCs can essentially always do this in a boss encounter, but lacks a generic solution that doesn't arbitrarily obviate Polymorph. There is nothing wrong with players using the strategy some of the time, and is only truly a problem if they start using it virtually all the time. It's the latter situation that indicates a closer-to-broken game.

Make things less predictable for your players

The biggest issue with this situation is that your players have identified a strategy that is reliably effective enough to be worth hazarding a spell slot to try essentially every significant-seeming boss fight. If you change that formula, you can disrupt that calculation.

My main go-to solutions in that direction are things like making spell slots directly useful in other ways (both using spells for other things, and using spell slots in novel ways, like to power magical constructions). But creativity is your friend-- the goal is ultimately to break the connection between Polymorph and easy boss fights in your players' minds. Wild magic fields that produce unpredictable consequences for casting higher-level spells, obstacles that break line-of-sight on the boss character, and magic-negating zones of the battlefield are examples of some other ways to disrupt the dominance of the strategy without just saying "Polymorph simply doesn't work here".

Concentrate on concentration

Since a character must concentrate on maintaining Polymorph to enjoy the benefits of this strategy, and a character can only concentrate on one spell at a time, you can adjust how desirable Polymorph is over other things your caster(s) might do. If the druid has another spell effect that requires concentration, making that a central part of the fight can prevent the Polymorph strategy from being attractive. You can also populate combats with mooks and traps designed to specifically force concentration checks.

Dispel Magic is easier to use than Polymorph

It's not that hard to toss a spellcaster or two into a fight, and even less difficult to give magic items to the NPCs. Access to something like a Wand of Dispel Magic, if you choose to homebrew such a thing, can make Polymorph-ing less worthwhile (much less worthwhile if the wand casts at 4th level or greater). Magic items that can cast Dispel Magic, or spellcaster NPCs, can also be used for things other than hard-countering Polymorph and so may not feel quite so targeted at the players' strategy.

Word spreads

A dominant strategy is a fun discovery for players, so letting them abuse it for a little while can be exciting for them. But there is no reason that their antagonists can't find out a bit about how the PCs are dealing with enemies, and so if they use this strategy more than a couple of times it's reasonable for their opponents to make preparations to deal with it.

Just say no

I, personally, dislike using this kind of approach and avoid it where I can, but sometimes there are no better options. There are hard counters to Polymorph, most notably giving your boss NPC Legendary Resistance or the Shapeshifter trait.

Talk to the players

One of the things that makes D&D exciting is the possibility of failure. If players devise a strategy that effectively cannot be beaten (short of the DM arbitrarily declaring that it's not going to work) then that element of the game is gone. I don't think that a Polymorph-based strategy necessarily fits that, but if you are averse to the hard counters and arbitrary rulings being in place all the time to prevent it you can wind up effectively in that spot. In such a case it's fair to say to your players something like

You've done it! You've won D&D-- without changing the rules, I'm not going to be able to design combat encounters you have a chance of winning without you being able to win them trivially. I'm open to other ideas if you have them, but if you want to keep playing this way then this campaign is basically over, because you've won D&D. Do you want to keep playing?

They may have other solutions in mind, but in my experience players prefer to limit their game-breaking activities over playing a game so broken that it has no excitement. It's a good opportunity to clearly mark that things will change, if not immediately then soon, to nerf the strategy and restore tension to the game.

When my players come up with what they think might be an overpowered approach and ask me about it, I generally tell them that even if it will work as they envision now it may not always work because I have a responsibility to keep the game fun and exciting-- I will not allow an I win button in the game. This has been enough to keep them from using those strategies all the time: it's more fun to have them available in a critical moment than it is to never get to use them at all.