Experiment: Incognito Monster

[Corsair]

Good ideas, but some unfortunate issues:

Dragon: I've already played a dragon character earlier in the campaign, and would prefer not to repeat that.

Makeup evil race: We had a non-evil drow do this already by a different player.

Changeling: A little too close to doppleganger for my liking.

Bralani: Hadn't considered this one, but looking over it, it feels like it might be a bit too underpowered for use as a character, especially at +5 LA. This is a problem I've found with many outsiders. They get one or two nice abilities, but the massive LA hit means they can drop to any appropriate challenge for the party.

Mephits: Interesting... 3 Outsider HD (not terrible at all) and only a +3 LA. What class would you suggest? An earth mephit with a hat of disguise would have decent strength (+6) to make up for lost BAB. I'd prefer a warrior or spellcaster (and yes I'm aware that making a decent spellcaster will be difficult)

Evil outsiders: nifty idea, but I'd prefer to stay away from giving the party any reason to want to off me.

 

[IcyCool]

Mephits: Interesting... 3 Outsider HD (not terrible at all) and only a +3 LA. What class would you suggest? An earth mephit with a hat of disguise would have decent strength (+6) to make up for lost BAB. I'd prefer a warrior or spellcaster (and yes I'm aware that making a decent spellcaster will be difficult)

I'm a tremendous fan of mephits. Mephit sorcerers aren't too shabby, but you'll be missing those higher level spells. An Air Mephit Bard could be fun too.

For a spellcaster, I'd recommend an Air Mephit (check out how their fast healing works), and one of the ground based mephits for a fighter type. For another odd critter, check out the Mephling in the Planar handbook. Sort of like a half-mephit. And they're only LA +1.

 

[Scratched_back]

Rakesha.... Reshecka... Rackackasesh....

The Tiger-headed folk from MM1 that began "R" and had a "sshhhh" sound in there somewhere.

Intelligent, tough, fighter/casters, master illusionists.

Ideal for what you lads are looking for.

 

[IcyCool]

You might also look into a Half-Janni from Sandstorm.

 

[andargor]

A few suggestions:

• Use the Spymaster prestige class from Complete Adventurer. Plenty of disguise abilities.
• Keeper (Fiend Folio), 4 HD, LA +3, Neutral, looks human or half-elven.
• Wispling (Fiend Folio), by character class, LA +1, looks like a halfling, usually evil but you can change that, Disguise Self
• Yuan-Ti pureblood (MM 3.5), 4 HD, LA +2, looks human (mostly), usually chaotic evil, +5 racial bonus to Disguise when impersonating a human
• Half-Ogre (Races of Destiny), by character class, LA +2, looks like a big human with odd skin
• Mongrelfolk (Races of Destiny), by character class, LA +0, passes for any parent race
• Unbodied (SRD 3.5), 4 HD, LA +4, psionic, Assume Likeness (Su) to pass as Small, Medium or Large creature

Andargor

 

[Nellisir]

An annis with a hat of disguise or a green hag. Maybe she's on a weird mission of her own. Maybe she wants to slap a few devils. Who knows?

A few levels of monk would go great with an annis. Give her elite stats and she'll be terrifying.

Cheers
Nell.

 

[FireLance]

How about an aranea (MM, p. 15):

ARANEA
Medium Magical Beast (Shapechanger)
Hit Dice: 3d10+6 (22 hp)
Initiative: +6
Speed: 50 ft. (10 squares), climb 25 ft.
Armor Class: 13 (+2 Dex, +1 natural), touch 12, flat-footed 11
Base Attack/Grapple: +3/+3
Attack: Bite +5 melee (1d6 plus poison) or web +5 ranged
Full Attack: Bite +5 melee (1d6 plus poison) or web +5 ranged
Space/Reach: 5 ft./5 ft.
Special Attacks: Poison, spells, web
Special Qualities: Change shape, darkvision 60 ft., low-light vision
Saves: Fort +5, Ref +5, Will +4
Abilities: Str 11, Dex 15, Con 14, Int 14, Wis 13, Cha 14
Skills: Climb +14, Concentration +8, Escape Artist +5, Jump +13, Listen +6, Spot +6
Feats: Improved Initiative, Iron Will (B), Weapon Finesse
Environment: Temperate forests
Organization: Solitary or colony (3–6)
Challenge Rating: 4
Treasure: Standard coins; double goods; standard items
Alignment: Usually neutral
Advancement: By character class
Level Adjustment: +4

An aranea is an intelligent, shapechanging spider with sorcerous powers. In its natural form, an aranea resembles a big spider, with a humpbacked body a little bigger than a human torso. It has fanged mandibles like a normal spider. Two small arms, each about 2 feet long, lie below the mandibles. Each arm has a hand with four many-jointed fingers and a double-jointed thumb.
An aranea weighs about 150 pounds. The hump on its back houses its brain.
Araneas speak Common and Sylvan.
COMBAT
An aranea avoids physical combat and uses its webs and spells when it can. In a battle, it tries to immobilize or distract the most aggressive opponents first. Araneas often subdue opponents for ransom.
Poison (Ex): Injury, Fortitude DC 13, initial damage 1d6 Str, secondary damage 2d6 Str. The save DC is Constitution-based.
Spells: An aranea casts spells as a 3rd-level sorcerer. It prefers illusions and enchantments and avoids fire spells.
Typical Sorcerer Spells Known (6/6; save DC 12 + spell level): 0— daze, detect magic, ghost sound, light, resistance; 1st—mage armor, silent image, sleep.
Web (Ex): In spider or hybrid form (see below), an aranea can throw a web up to six times per day. This is similar to an attack with a net but has a maximum range of 50 feet, with a range increment of 10 feet, and is effective against targets of up to Large size. The web anchors the target in place, allowing no movement.
An entangled creature can escape with a DC 13 Escape Artist check or burst the web with a DC 17 Strength check. The check DCs are Constitution-based, and the Strength check DC includes a +4 racial bonus. The web has 6 hit points, hardness 0, and takes double damage from fire.
Change Shape (Su): An aranea's natural form is that of a Medium monstrous spider. It can assume two other forms. The first is a unique Small or Medium humanoid; an aranea in its humanoid form always assumes the same appearance and traits, much as a lycanthrope would. In humanoid form, an aranea cannot use its bite attack, webs, or poison.
The second form is a Medium spider–humanoid hybrid. In hybrid form, an aranea looks like a Medium humanoid at first glance, but a DC 18 Spot check reveals the creature’s fangs and spinnerets. The aranea retains its bite attack, webs, and poison in this form, and can also wield weapons or wear armor. When in hybrid form, an aranea’s speed is 30 feet (6 squares).
An aranea remains in one form until it chooses to assume a new one. A change in form cannot be dispelled, nor does an aranea revert to its natural form when killed. A true seeing spell, however, reveals its natural form if it is in humanoid or hybrid form.
Skills: Araneas have a +2 racial bonus on Jump, Listen, and Spot checks. They have a +8 racial bonus on Climb checks and can always choose to take 10 on Climb checks even if rushed or threatened.

Give it levels of sorcerer or a mix of fighter and sorcerer levels and go eldritch knight or spellsword. Make its alternate form that of a female elf, and when the party discovers she has spider-like characteristics, let them get all paranoid about Lolth (the non-evil drow, in particular).

 

[Teemu]

How about the phasm? They're core, they're weird, and they're excellent shapeshifters.

 

[red eyed antipaladin]

How monstrous does it have to be? For example, would an evil PC-race character be acceptable?

A human with a Hat of Disguise (or a changeling, if you're willing to bend on the pseudo-doppleganger thing) Warlock 5 (C Arcane)/Chameleon 5 (Races of Destiny, although it isn't on your list. If you don't have the book, the class appears in the preview for RoD on the WotC website.) makes a great infiltrator into any party. Their Eldritch Blast gves them an effective backup weapon, and depending on invocation choices they can be stealthy, social or athletic. Add-in the Chameleon's ability to pretend to be almost any class, and you've got a winning combo (and curiously, Warlock is actually the easiest path to Chameleon. I don't think they intended that, but anyway...)

 

[Piratecat]

The MM2 has a really neat aberration associated with undead, and they're great shapeshifters. They're absolutely completely bizarre. I'll check the name when I have a chance.