unsolved problem—and don’t even ask about how a worm moves up and down, or, for that matter, why. All of the data we have about C. elegans behavior comes from worms in flat agar plates.

Also found on a submarine canyon floor: a deep-sea worm sometimes called a "disco worm," but scientifically known as a polychaete (which means “many bristles”), glittering like sparkly steel wool.