Black Dragon Cauldron in Yellowstone National Park. This is one of the mud pots located near Mud Volcano. This place absolutely has been most accurately named. Besides the steam and the heat sprewing from within, and the stench (hydrogen sulfide) and the blackened burnt look (iron sulfide) in the area; the histroy of its birth makes it sound like a real dragon lives within. To borrow the words from the NPS website ... "Black Dragon Cauldron did not exist before 1948. It exploded into existence sometime before June of 1948, knocking trees down and showering the surrounding forest with mud." Dragon's Mouth Spring is also in this area.