The seafloor is mostly flat and smooth, reflecting sedimentation, the dominating seabed formation mode. In this communication, I shall focus on how vertical fluid flow, also called “seepage” may alter and imprint the seafloor geomorphology. Seafloor seeps occur globally, wherever a fluid (gas or liquid) resides in the sub-strata below the seafloor and finds a way up. The fluids may come up from depths of several kilometres below surface or from shallower depths. Because they have lower specific gravity than their surroundings, they tend to move through the pore-spaces of sediments or fissure-networks of solid rocks, and upwards towards the surface. At locations where they break through the seafloor, depressions and sometimes mounds may form (Fig. 1).