Sure, mud volcanoes aren't nearly as dangerous as their cousins of the magmatic variety, but when they do actually erupt, it's not exactly a pretty sight. In 2001, a new island grew out of the Caspian Sea, due to an increase in volcanic activity—right nearby where hundreds of these bad boys are. Generally, they go off every twenty years, and when they do, they shoot flames "hundreds of meters into the sky" and deposit tons of mud into the immediate area. Try wrestling your way out of that mud.