There are three men on a boat. A Serb, a Bulgarian, and an Arnaut. Sea monster shows up and tells them that he will kill them if they can't throw something he can't find into the ocean. The Arnaut throws in a grain of rice. Sea monster dives in and comes back with the rice after a few hours. He kills the Arnaut. The Serb throws a grain of sand into the ocean. After a few days, sea monster retrieves it and kills the Serb.
Sea monster looks expectantly at the Bulgarian, who then proceeds to throw an Alka-Seltzer into the ocean.