Are there a Body Snatchers in the House?

[Prometheus]

I'm looking for a creature that can take the form of the last victim it's destroyed by taking its body or skin. There is tons of legends about them, but I don't know that D&D has any. Something that can merely shapeshift, or gain some other benefit from defeating a foe, or can turn a foe into its species does not count.

The only one I know is Reason Stealer, and that is very unsatisfactory in terms of disguise but I know there has to be one somewhere. If there are multiple ones that fit the description, which do you like the best?

[Collin152]

The closest I can think of is the Devourer, and it isn't even close.
Maybe Hellwasp swarms?

[AslanCross]

Check out the Skindancer. (Monsters of Faerun)

EDIT: My bad, it's in Monster Manual 3.

EDIT again: My bad, apparently it doesn't take the form of its last victim. I know they used to (at least Baldur's Gate II had them doing this), but they don't have that ability anymore, apparently.

Best I can think of is a Rakshasa assassin with a serial killer attitude.

[Admiral Squish]

Intellect devourer.

[Gralamin]

Tsochar, The Wearers of Flesh from Lords of Madness

[holywhippet]

The doppelganger comes close. I don't think it needs a flesh sample though, it just changes shape and uses read thoughts to impersonate them well.

[martyboy74]

Tsochar, The Wearers of Flesh from Lords of Madness

These are the ones you want. They're nasty little buggers, and your players almost certainly won't've heard heard of them, let alone know anything about them.

[Fizban]

Additionally, the MMV has a bunch of Thoon related monsters, one of which can implant mind-controlling parasites. As a bonus, when forced into combat, the possessed gains hp until it explodes.

[The_Snark]

The Greater Doppelganger (Monsters of Faerun) does this, absorbing memories and personality completely.

[AslanCross]

Tsochar, The Wearers of Flesh from Lords of Madness

Now that the Tsochar have been mentioned, I'll have to second this. They're freaky, really alien things. I recommend them.

[CthulhuM]

There's a prestige class from BoVD called the mortal hunter that gives pretty much exactly the ability you're looking for. Mortal hunters can graft bits of their victim's flesh onto theirs in order to gain the ability to transform into them. In theory, the class can only be taken by outsiders (it's meant to be mainly for demons and devils), but you're obviously free to ignore that if you want.

[Parvum]

Hellwasp swarms are fun. Though, the victim doesn't have to be dead (but that might just make it more fun).

[Collin152]

Hellwasp swarms are fun. Though, the victim doesn't have to be dead (but that might just make it more fun).

They will be soon enough.