Sea Monster is the boss of Ocean World in Parasol Stars. It is a sea creature with a volcano on its back.
Jump up to snag the Lighting Bottle immediately, followed by getting to the very edge of the top platform. Now wait for the beast to rise up high enough so a Charged up Lightning blast can hit the monster, all the while hopping straight up to avoid the fireball attacks that are far enough to hit Bubby and Bobby. Land five fully Charged shots to extinguish this beast and it's over powering Volcano to move onto the next world!