Courtesy http://www.worldwidewords.org/
ADIPOCERE 
Post-mortem waxy fat.
This is mostly met with by forensic medical experts, hence its other name of mortuary fat.
It’s a greyish-white or yellow waxy substance that forms from the fat
of certain parts of dead bodies, especially if they have been buried in
wet places. The changes occur quite quickly and can accompany a form of
natural mummification. It’s known to occur in ancient bog bodies and in
those preserved in ice, such as the Alpine man Ötzi. It’s also
encountered sometimes by archaeologists investigating relatively modern
sites containing burials; an example was the difficult and harrowing
excavation in the crypt of Christ Church Cathedral in Spitalfields,
London, in the early 1980s. The word derives, via French, in which
language the word was first employed in the late eighteenth century,
from the Latin adipis, “fat” (as in adipose tissue), and cera, “wax”.