Dragonzamasu
Dragonzamasu is the second boss of the game Super Mario Land. He is a large Yurarin (a seahorse-like dragon) that lives underwater. During the extraterrestrial invasion of Sarasaland, the evil space alien Tatanga placed Dragonzamasu in charge of the Muda Kingdom, the second world of Sarasaland. In the third level of this world, Mario battles Dragonzamasu in the monster’s water-filled lair. However, since they are underwater, Mario has to fight Dragonzamasu with his custom submarine, the Marine Pop. To defeat Dragonzamasu, Mario had to fire torpedoes at the monster and succeed in hitting it 20 times. Dragonzamasu was protected by bubble barriers called Tamao. His defeat was worth 5000 points.
Interestingly enough, the Dragonzamasu fight is the first shooter battle in any Mario game.