In trying to set reasonable limits on a PC's usage of the polymorph chain of spells. Is it plausible to require that the PC have some form of interaction with the target creature? Or can a PC polymorph into a creature that the PC has only heard about? Or read about in a book? Or seen just a painting of? From a solid role-playing standpoint, it seems reasonable to require that a) the creature exists in the multi-verse that the DM is running, and B) the PC has some knowledge of the creature. What is the minimum "knowledge" that the PC must have in order to polymorph into such creature?


6 Answers 6


In my opinion, you should at least have encountered the creature before to polymorph into it. You might even have to examine a body. Reading about it in a book or rolling Knowledge should only let you recognize it.

  1. It lets the DM prohibit creatures with abilities that are broken in the hands of PCs, or creatures which don't exist in his game world.
  2. It adds realism. How can someone who's never seen an ettercap expect to replicate its form, let alone its poison glands?
  3. If the player really wants a certain form, they can go and hunt down a creature of that type, and this can be the seed for an adventure.
  4. It prevents the player from assuming the forms of high-powered, low-HD creatures that would normally be above their challenge rating. However, this is rarely an issue since creatures with low HD for their CR creatures tend to get their power from supernatural abilities that you don't get with polymorph.
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    \$\begingroup\$ Re: #2. I dunno, how about... magic! :-) I don't disagree with your conclusion but arguing 'realism' for how magic works is silly. \$\endgroup\$ Dec 20, 2012 at 21:57
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    \$\begingroup\$ A better word than "realism" might be "verisimilitude". \$\endgroup\$
    – cr0m
    Dec 21, 2012 at 0:02
  • \$\begingroup\$ Verisimilitude, right. The quality of seeming real, rather than being true to the real world. \$\endgroup\$ Dec 21, 2012 at 11:39
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    \$\begingroup\$ Even by verisimilitude standards, shape change effects only working for people with a high degree of anatomical knowledge only really makes sense for INT-based casters. Druids change into whatever based on the supernatural power of nature and sorcerers from their own mojo. Remember that every single power from a non INT caster works just as well with an INT of 3 as it does with a 25. \$\endgroup\$ Dec 21, 2012 at 14:14

Polymorph Effects Are Dangerous

It is a very good idea to limit them. At the extreme, changing into a Sarrukh from Serpent Kingdoms while using Assume Supernatural Ability (Savage Species) or shapechange is the opening gambit for becoming Pun-pun, a character with +Yes to everything and every ability ever published (and arguably abilities not published, as well).

So you definitely want to limit them somehow.

This Rule is Not Enough

If you implement this rule, you will now have to second-guess every monster you ever use. You’ll probably never use a Sarrukh, but you might use, say, a Dire Tortoise (Sandstorm). A smart Wizard or Druid will see that, and from then on get to act in every Surprise Round ever – even if there wouldn’t otherwise be a Surprise Round. You can, of course, nerf the Dire Tortoise, but a lot of players will cry foul if you do that after you used it.

Two Real Solutions

Trust Your Players

This is the simple one. You don’t even need to add your houserule if you just trust your players. I’d really strongly suggest that, if you cannot trust your players, your group has bigger problems than Polymorph. Make it clear to all players that Polymorphing is something very dangerously powerful, and you will not appreciate it if players use it to break the game. That should be enough for most players to keep things reasonable.

Thematically, you may want certain limits, but you don’t have to say it’s specifically having encountered the animal. It seems thematically appropriate for a Wizard to be able to take the forms of animals he’s studied in intimate detail. And it’s also fair for a Druid to include encounters with a variety of animals in his backstory, and you could argue that Nature/the spirits of animals themselves are lending him their forms, even creatures he’s never met. It depends on how magic works in your setting.

Ban Open-Ended Polymorph Effects Altogether

Replace the Druid’s Wild Shape with Shapeshifting from Player’s Handbook II. Ban alter self, polymorph, polymorph any object, and shapechange. Use the spells from the [Polymorph] subschool introduced in Player’s Handbook II – unlike e.g. polymorph, those spells each have a single form you can take.

Alternatively, you might consider a spell that is like wild shape I that lets you turn into a creature from the summon nature’s ally I list, or a polymorph III that lets you get creatures from summon monster III. Those lists are rather limited and should prevent the greatest abuses. In fact, they may be too weak – consider having wild shape I use the summon nature’s ally II list, and polymorph I might even use summon monster III – the Celestial and Fiendish templates really do very little for a player character, since the main draw is the Intelligence bonus. I have not actually looked at the lists, though. Ideally, really, you’d create all-new lists that are tailored to each level.

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    \$\begingroup\$ Additional options: using the Pathfinder version of Polymorph. Requiring the wizard/druid/whatever to have a part of the animal on him to be able to take its form (as a F component): can be found on corpses if not too damaged (hint: if it's a problematic form, it's "too damaged"), or sometimes bought in component shops \$\endgroup\$ Dec 20, 2012 at 8:13

Yes, it is plausible to restrict polymorph to creatures that the players have encountered. This is one of the commonly discussed polymorph house-rule.

I think the minimum knowledge would be determined by a knowledge skill check for that monster. If the monster does not exist in your multi-verse this check would be impossible to complete. Basic knowledge of a monster starts at 10+HD, but I would extend this to be 10+HD+X, where X is creature dependent (maybe based on the number of special abilities the creature has).

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    \$\begingroup\$ Can you expand on your answer any? What does the knowledge check represent? Does it make sense that a character can transform into a mind flayer if the character has only ever heard of a mind flayer in tales but has never seen a visual representation of one? \$\endgroup\$ Dec 19, 2012 at 21:00
  • \$\begingroup\$ As a DM, I would say the knowledge check varies by creature. Planar/Elemental creatures would be Knowledge(Planes), common monsters would be Knowledge(Dungeoneering), magical creatures would be Knowledge(Arcana), and so forth. For a creature they've never encountered in person I would call it at least a DC 20 + HD + X and a creature they have encountered call it a DC 10 + HD + X. \$\endgroup\$
    – BBlake
    Dec 19, 2012 at 21:13

I've taken to a risk v reward method for Polymorph. I make only one simple alteration. If you nat-1 on a Polymorph, you accidentally summon whatever you were trying to alter yourself or others into.

Nice and tidy, it deters anyone from doing anything too terrible or dangerous and is rare enough that occasional massive risk can result in great fortune. It retains the power of the spell, while preventing it from being abused.

A potential addition that I considered but didn't include was increasing the failure rate for monsters that the player hasn't encountered before or hasn't passed a knowledge test to know about. That could work, but the risk of accidentally making the battle unwinnable seems to be enough for my players.

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    \$\begingroup\$ @MarkRogers lol. I like that my hat is for posting tomorrow... How does it know! \$\endgroup\$
    – DampeS8N
    Dec 20, 2012 at 18:12

Once I used a table based on the teleport tagert table, it was something like it:

Familiarity          Fails/Wrong Monster     Weak Version     Exact Monster  

Very familiar                                 1                 2-20       
Studied carefully     1                       2-3               4-20      
Seen casually         1-2                     3-5               6-20
Viewed once           1-4                     5-8               9-20 
Read or saw picture   1-8                     9-15             16-20
Monster doesn't exist 1-19                    20

With fails/wrong monster I would jut choose some monster or animal visually resembling the monster but very weak, or totally opposed thing, "So, let me see, you turned into a... Giraffe..."...

A weak version could be the same monster, but without power, or attributes modifies reduced, like instead of +8 in Str, you get +2, etc..

You could fine tune the checks using the CR of the target and the caster level of the character


I recommend handling polymorph spells the following way: The player casts polymorph, wildshape, etc and tells the table what he's turning into. If anyone at the table then exclaims any of the following phrases: 'What?!', 'The hell book is that from?', '', 'That's (ridiculous/stupid/a travesty)', 'Quit being a douche', or 'Nuh-uh', then the casting fails and he gets to try again next round.

The best solution for all player problems isn't codifying a rule base to eliminate abuse, it's making it immediately clear that Player X's shenanigans are making the other people at the table have less fun.

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    \$\begingroup\$ The problem with this solution is that it will not work with all groups of players. I've played in plenty of games where players turn finding rules 'exploits' such as these into a sport, and would actively support someone casting this kind of thing. \$\endgroup\$
    – Wibbs
    Dec 20, 2012 at 23:03
  • \$\begingroup\$ Well if everyone's having fun, then it's by definition not a problem. \$\endgroup\$ Dec 21, 2012 at 0:40
  • \$\begingroup\$ That definition you give of everyone doesnt necessarily include the GM though \$\endgroup\$
    – Wibbs
    Dec 21, 2012 at 8:47
  • \$\begingroup\$ Is the DM of your games not a person at your table? How unconventional of you. \$\endgroup\$ Dec 21, 2012 at 14:17

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