We investigated splash produced by spherical object plunging to water surface. We focused on the effect of swelling of object which was made of hydro gel. We compared the splash versus of swelling of the object. The splash form we observed was crown-type that is formed by water jets with many droplets. The height of splash became higher as swelling increased, and the speed of the object sinking in the water also became higher. The velocity around the object increased according to swelling. The gel surface of object was effective for the reduction of friction of an object moving in liquid.