Overview:Attacks by mountain lions make headlines across the U.S. But some people say they are seeing something else...large black cats. From Texas to Minnesota to West Virginia, MonsterQuest will follow the eyewitness accounts and physical evidence of these demon cats. Pictures and law enforcement encounters prove a big black cat is out there but what is it? While they resemble a mountain lion, there is no such thing as a black mountain lion. Bones from a carcass, eyewitnesses claim was a huge black cat, will be put to the DNA test.