This is a photoscan of a highly realistic skull model with some cleanup work done to the mesh and texture. I've brought down the polycount from around 2.4 million to the 934,000 it's at here, and the texture from 12k to 2k.
Note: May cause slowdown on some computers (mainly those without dedicated graphics cards)
EDIT 17/07/2016: I've now made this model free to download but only on a non commercial license since I didn't create the original object the scan is of, outside of this you may use the model as you wish