With this technique, the user can take on the properties of a nearby object, material, or substance. For example, Nagare took on the properties of a rock and was then able to use his imitation of other techniques, like Assimilation: Rock Blizzard and Assimilation: Sand Waterfall Funeral. He was also able to turn his skin to rock, either entirely or partly, and could even survive being blown to bits by simply assembling himself.
Trivia
Shinra Banshō (森羅万象; Literally meaning "All-Covering Forests and Ten Thousand Things") is a Buddhist idiom which has come to mean "All of Nature" or "All of Creation".