Animé show. Involving a cast of demons, half-demons, and humans in feudal
Japan.
The shape-shifter is Naraku, the series' main villain, whose true form is
never seen. He wears the form of InuYasha (the hero), Kikyo (a female lead),
Lord Hitomi (a dead human [Naraku replaces him] who serves as Naraku's usual
face), a baboon-masked hermit, a giant spider-demon, and an amorphous mass
of writhing demon parts.
He can also use his shape-shifting in a variety of ways, including extruding
parts of himself that become new demons, absorbing other demons, and
inhabiting demons and humans so they'll carry him around unaware (used once
to fake his death).
Mark
"He's also just generally really creepy."