Thanks to reader B. D. for sending me the link to this video. A young man decides to throw a pound of sodium into a river. The results are . . . well, see for yourself. Watch in full-screen mode for best results.
Of course, by chucking that much sodium into the water, he also poisoned that stretch for fish and other wildlife, at least until the concentrated solution got diluted . . . but I guess he wasn't thinking about that.