Kingfin

Kingfin is a boss in  Super Mario Galaxy. In the Prima Games Guide book, an issue of Nintendo Power, and in his Super Mario Galaxy trading card, he is mistakenly called "the Bonefin", possibly because the name of its galaxy is Bonefin Galaxy. Its name is most likely a pun on the word "kingpin", which refers to the most important person in an undertaking or organization, such as a galaxy boss. Kingfin commands a legion of Fishbones and is himself a skeletal shark, although in actuality, sharks are cartilaginous and do not have bones. Kingfin also has beams of light shining out of his eyes when battling Mario. However, if the player uses Luigi, his eyes do not shine. Through a simple glitch, the eyes won't shine if the player uses Mario, when the player bothers Luigi in the Observatory (spinning at his proximity/jumping on him for example) before entering the Bonefin Galaxy.

In battle, Kingfin has the power to summon large hoards of angry Fishbones from the craters in the center of the planet, which attack in the same way as Torpedo Teds, homing in on the player from all directions. The more damage Kingfin takes, the more Fishbones it will summon to attack Mario. The theme music in the battle with Kingfin is the same with Bouldergeist. However, when Mario or Luigi comes closer to Kingfin, a percussion beat is added to the background music. The music speeds up once Kingfin has taken damage three times.

Battle
When Mario enters the waters of Kingfin's planet, Kingfin will appear with some Fishbones that track Mario down to attack him. There are only two ways for Mario and Luigi to defeat these Fishbones; they must lure them to the surface or into a wall, or throw a shell at them, which causes them to drop three Star Bits upon impact. If the fish touch the surface they will automatically explode. If Mario touches Kingfin, he will lose health. The only way to defeat Kingfin is to grab a Green Shell or a Red Shell from the seafloor of the planet and spin to launch it at Kingfin. After one hit, two Fishbones will attack Mario. After two more hits, four Fishbones appear to attack him. Once Kingfin has been hit a total of five times with shells, he will explode and release a Power Star. The battle can be made easier with the help of a Life Mushroom hidden in a pillar, as well as a submerged treasure chest, which contains the only 1-Up Mushroom in the level. The pillars are destroyed by Kingfin ploughing through them; he destroys two shortly after getting hit once, and he destroys two more after taking another two hits.

Trivia

 * Kingfin shares his boss music with Bouldergeist, and a percussion beat is added to his music as well, but when the player is close to Kingfin.
 * His explosion/defeat animation is very similar to that of his Fishbones.
 * The name 'Kingfin' is most likely referencing the word 'Kingpin', which is a reference to the title crime lord in mafia slang nomenclature.