Spawns of Leviathan are enemies in Castlevania: Lords of ShadowReverie DLC. They are the spawn of one of the Old Gods. More an environmental hazard than a true enemy, Spawns of Leviathan cannot be fought: their purpose is to punish the player if they allow Gabriel to fall into the water during platforming sections by immediately devouring him.
"The dark waters that fill the caverns beneath the castle hide a creature whose name was forgotten long ago by men, one of the Old Gods themselves, who was attracted by the evil within this place and its imprisoned inhabitant.(...)"