Marvenkens are sea creatures that prey specifically on sailors and passengers to small- to medium-sized boats. Although they typically dwell near the bottom of whatever body of water they've called home, any time a marvenken finds something shiny along the ocean floor they will float closer to the surface in search of boats and unassuming victims. By holding the shiny object in their mouth, they'll reflect sunlight towards the boat to draw attention to itself and hold the object just beneath the surface, as if offering it to the ship's passenger. If their prey reaches into the water to grab the object, the marvenken will quickly wrap a dozen tentacled appendages around whatever they can and pull their dinner into the water, where it is quickly dragged back down into the depths and never seen again.