A mudpot, or mud pool, is a type of acidic hot spring, or fumarole, with limited water. It usually takes the form of a pool of bubbling mud. The acid and microorganisms decompose surrounding rock into clay and mud. The mud of a mudpot takes the form of a viscous, often bubbling, slurry. As the boiling mud is often squirted over the brims of the mudpot, a sort of mini-volcano of mud starts to build up, sometimes reaching heights of 1 to 1.5 meters (3 to 5 ft). The mud is generally of white to greyish color, sometimes stained with reddish or pink spots from iron compounds. When the slurry is particularly colorful, the feature may be referred to as a paint pot. This video of a bubbling mudpot was captured in Lassen Volcanic National Park in northern California.Video credit: Frank Schulenburg