golem can be stretched to meet the OP's definition. Oxford Dictionaries defines golem as:
1(in Jewish legend) a clay figure brought to life by magic.
1.1 An automaton or robot
Oxford Dictionaries (same link as above) explains the origin:
Late 19th century: from Yiddish goylem, from Hebrew gōlem ‘shapeless
Merriam Webster says:
1 : an artificial human being in Hebrew folklore endowed with life
2 : something or someone resembling a golem: such as a : automaton
b : blockhead
Although the original meaning was a clay or mud figure brought to life by magic, because the meaning has been extended to a robot or automaton -- or a blockhead! -- I see no reason why it cannot also be extended to a being made from the body parts of dead people.
The body parts are inanimate, will turn into dirt eventually, and are much closer to clay or mud that are the parts of a robot. Jumbled in a heap, or if they have been dead long enough, they are shapeless. And if the creator of the golem puts the parts through a industrial size mix-master so he can mold the shape of his golem, rather than assemble it jig-saw puzzle fashion, golem is indisputably the word.