According to his account he received instructions in a dream from five humanoids who showed him the spot where he was supposed to dig.
The Director of the Paleontology Museum of Asenovgrad had a chance to examine it and said it resembles nothing he had ever seen.
Theories about its origin range from remains of ancient failed genetic experiment to hastily buried alien but until today, no one has been able to offer conclusive details about what the mysterious skull is. All we can say with certainty is that it actually looks like the skull of an alien creature.
Video below: The Rhodope skull 360 degrees view.