Outwitting a doppleganger

[ScionofImperius]

is there any spell, (i'm AFB) that can force a doppleganger to revert back to its original shape? I know that a thin sheet of lead will stop its mind reading ability, but I need to prove that the doppleganger is such. any ideas?

[Khatoblepas]

Discern Shapechanger is a 3rd level spell that lets you see the true forms of any shapechangers around, no save.

Church Inquisitor 6 will allow you to spam around dispels for shapechangers:


Force Shapechange (Su): A church inquisitor of 6th level or higher can force a creature into its natural form.
The church inquisitor must make a successful melee touch atack against the creature. If the attack is successful, the
church inquisitor makes a caster level check as if casting dispel magic against the shapechanging effect. The church
inquisitor's +4 bonus on dispel checks (the Inquisition domain granted power) applies to this check. This ability
undoes the effect of alter self, polymorph, shapechange, and any alternate form abilities, whether exceptional, spell-like, or
supernatural in nature. The affected creature cannot change its shape again for 1d6 rounds. The church inquisitor can use
this ability at will.
So you can just keep slapping the shapechanger once you've found him until he turns back. You might even be able to punch him back to normal.

[Kelb_Panthera]

There's a couple of spells in Races of Eberron that can ruin a shapechanger's day. Note that in spite of the fluff and the word Eberron in the title, RoE was intended as a supplement to be used in any game, and any setting.

[Mithril Leaf]

If you're a wizard with improved familiar, you can get a beguiler with infinite true seeing at level 7. Not quite what you were looking for, but for arcane casters, it's a port in a storm.

[Slipperychicken]

Detect Thoughts (sorc/wiz 2, some other classes get it as well) might work too. If you can get him to fail a Will save, you should be able to ask him about shapeshifting or shapeshifters, or how much you hate dopplegangers. He'll think about how he's a doppleganger himself, and that's all the proof you need.

IIRC, it's a DC 100 Bluff to disguise surface thoughts, so its just a matter of asking the right questions. Take his magic items away so he can't pump his Bluff check with those.

Probe Thoughts (SpC, sorc/wiz6) and Mindrape (BoVD, sorc/wiz9) give slightly-better effects. Probe Thoughts lets you telepathically ask questions which he answers truthfully and to the best of his knowledge, and Mindrape gives you everything he knows instantaneously.

If the ability is not extraordinary, AMF should shut it down.

If it's spell-like, not supernatural, Dispel Magic can do it too, although you have to succeed on a Dispel check.

[Kelb_Panthera]

Fun fact: dopplegangers can look like anybody, but they're still limited by their own capabilities.

If the doppleganger is pretending to be a character with PC levels, you can out him by challenging him to do something someone of his class can do, that he can't because he's faking.

IE challenge him to turn undead or smite evil or cast a spell or fly into a rage etc.

Note that this approach is pretty much worthless if he's got chameleon levels.

[LanSlyde]

Fun fact: dopplegangers can look like anybody, but they're still limited by their own capabilities.

If the doppleganger is pretending to be a character with PC levels, you can out him by challenging him to do something someone of his class can do, that he can't because he's faking.

IE challenge him to turn undead or smite evil or cast a spell or fly into a rage etc.

Note that this approach is pretty much worthless if he's got chameleon levels.

Or a stupid high bluff check

[Kelb_Panthera]

Or a stupid high bluff check

How can a high bluff check account for the fact your waving hands and babbled gibberish accomplished nothing? Lying doesn't help much when you're called to task for actual proof.

[LanSlyde]

How can a high bluff check account for the fact your waving hands and babbled gibberish accomplished nothing? Lying doesn't help much when you're called to task for actual proof.

Clearly you haven't been keeping up with OotS.

http://www.giantitp.com/comics/oots0767.html

[Kelb_Panthera]

Clearly you haven't been keeping up with OotS.

http://www.giantitp.com/comics/oots0767.html

I have indeed, great comic. Not exactly a solid argument for any kind of rules lawyering though.

A series of impressive bluff checks, with a significant penalty, might be able to convince people that the doppleganger is who he says, but that something's wrong with him.

Ineffective isn't quite as bad as imposter, but it's a hard blow to just take, and if shown consistently it can become proof of an imposter, or it can make whether he's an imposter or not irrelavent by making the people he's fooling want him to just go away in any case, since he can't do anything useful.

[roguemetal]

Best way to outwit a doppleganger? Provoke both the character in question and the doppleganger to produce material evidence and answer the same questions in separate locations. The doppleganger cannot read minds from a good enough distance, or cannot produce the proper identifying evidence without magic to sustain it ideally.

If this is not your standard doppleganger, another solution is to use spells or poisons that only target humanoids.

If the powers of the doppleganger go beyond that, kill them both, and hope one reverts once killed, and resurrect the other. To save level loss, ensure a 50/50 chance of getting it right by killing them one at a time.

Oh, and if one of them has a goatee and the other doesnt...

[Kelb_Panthera]

Beware the super-dopplegangers. Greater doppleganger in monstrous compendium: monsters of faerun, and ethereal doppleganger from MM2 are both capable of much more than your standard doppleganger.

[JeminiZero]

Let me take the chance to plug one of my favorite divine spells of all time: Sacred Item (http://www.giantitp.com/forums/showthread.php?p=13206165#post13206165) [Complete Champion pg 126]. Permanent until discharged, triggers when touched by an undead, evil outsider, or evil shapechanger. This makes it generally useful not just for busting evil doppels, but also succubi pretending to be damsels in distress.

Permanent until discharged, means that you could commission a spellcaster to put it on an item for 280 gp (http://yasa.nycmongol.com/spellcost.html) (level 4 spell, level 7 caster), and then touch the item against a suspect, and it will go off when the suspect is any one of the above. E.g. you could store it in a ring, and if you suspect somebody is an evil shapechanger in disguise, offer to shake their hand while wearing the ring.

Another alternative is true seeing. While generally expensive, the Scout's Headband [MiC 132] provides 1 minute of true seeing per day, for 3,400 gp, which is probably the lowest price entry point. You can even buy several, and swap them out.

[Downysole]

Specific to the Doppleganger Entry in the MM, it says that True Seeing sees the doppleganger as it's oddly alien-looking form.

Or you could just kill it and then it would revert to that form too. True Seeing costs 250 gp for material components, but Raise Dead costs 5,000 gp. So, is it worth risking the 4,750 gp to kill someone who really isn't a doppleganger and then raising them? I'd say it depends on whether you want to see the look on your DM's face.

[Prime32]

Beware the super-dopplegangers. Greater doppleganger in monstrous compendium: monsters of faerun, and ethereal doppleganger from MM2 are both capable of much more than your standard doppleganger.The greater doppelganger has to eat its victim's brain though. It also can't duplicate abilities granted by deities, though that might be altered outside Forgotten Realms (where deities are really important and active).