text: When a liquid drop strikes a wet solid surface (a surface covered with a thin layer of liquid that exceeds the height of surface roughness), either spreading or splashing will occur. If the velocity is below a critical value, the liquid will spread on the surface, similar to deposition described above. If the velocity exceeds the critical velocity, splashing will occur and shock wave can be generated. Splashing on thin fluid films occurs in the form of a corona, similar to that seen for dry solid surfaces. Under proper conditions, droplet hitting a liquid interface can also display a superhydrophobic-like bouncing, characterized by the contact time, spreading dynamics and restitution coefficient independent of the underlying liquid properties.