In his book Mirages on the Sea of Time (which I plan to return to) Edward Schafer describes a monstrous mollusc with many of the traits of Hugo’s horrible octopus:
In imaginative literature, particularly, but also in some soberer sources, the ch’en mollusc acquired more extravagant attributes. It was transformed into a monster lurking in dark lairs — mysterious submarine grottoes — where it assimilated some of the traits of a sea-dragon, frothing at its ambiguous mouth and belching bubbles into the world of man, in a way somewhat reminiscent of the occidental dragon crouched over its kingly hoard and spouting puffs of smoke and fire:
“He worked his jowls and dripped saliva, gaping and sucking, so that people took him to be a veritable sea-basilisk [kraken, giant squid ] or dragon-clam [clam-monster]“.
Edward Schafer, Mirages on the Sea of Time, California, 1985, p. 81
Oddly, this mythical creature (like the dragon “hid in the deep”, of which it may be a prototype or relative) is not regarded as evil. It’s merely one of the strange creatures living in an undersea Taoist fairyland corresponding to the terrestrial Kun Lun Mountain fairyland, and its most prominent power is the creation of the strange nautical mirages or fata morganas which sometimes confuse sailors. Schafer speaks of it as a kind of clam, but it behaves more like a cephalopod, and Schafer probably should have treated it as one (or perhaps, since it’s mythical, as a hybrid clam-squid.)
Whether the Taoist clam monsters have anything to do with the thetan clams who have left bivalve engrams deep in our psyches, or with the Pirates of the Caribbean Kraken, is unknown to me.