It wasn’t gloom at all, really. There were lights and colors. If it hadn’t been for the feel of the water gliding by against his skin he might have imagined himself up in the sky, with meteors and comets blazing past. But these were sea-things, shining in the dark, the luminous life that blazes beneath the southern sea.
First he’d see a tiny twinkling speck, like a star, and it might have been next to his face or a mile away, in that immense, featureless void, with its faint hint of green. It would grow larger. It would turn into a radiant sun of purple or crimson or orange and come rushing at him, and swerve aside at the last moment. There were sinuous ribbons of fire that coiled into bright patterns, and there were schools of tiny fish that flashed by like sparks. Down below, in the deeper abyss, the colors were paler, and once an enormous shape blundered past down there, like the sea-bottom itself moving heavily. Pete watched awhile and then swam up.
—Before I Wake (excerpt) by Henry Kuttner
Iz Us by Aphex Twin