Super Mario Sunshine Bosses
Below is a Super Mario Sunshine Boss guide that will give you the neccesary information to find the weakness of and defeat all of the bosses in Super Mario Sunshine.
How to Defeat Super Mario Sunsine Bosses
Polluted Piranha Plant
You'll be fighting these guys five times throughout the first areas of the game, so be prepared! Other then being one of the most common bosses, these guys are also the easiest. Just watch out for the enemies that consistently spawn in the goop, as they will make this fight about twice as hard. As the Piranha Plant opens it's mouth, simply spray into it. Spraying the plant enough times when it's mouth is not open will cause it's head to go back into the goop generator, and you will have to restart the entire fight.
Petey Piranha is found in Episodes 2 and 5 of Bianco Hills. In episode 2, after reaching the top of the windmill and falling down into the arena, quickly begin cleaning off all the goop on the ground. Not only will this goop damage you given enough time, but it will also spawn Swoopin Stus. As he opens his mouth and begins to breath in, spray water into it. After you have sprayed water long enough, he collapse and his belly button will appear. Ground pound it to do damage. In episode 5 of Bianco Hills, he is found sleeping. Simply spray him to wake him up, and he will begin flying. This boss battle is slightly different in that he will fly occasionally dropping goop as he goes. Spray him in the air when he stops moving and he will fall down, allowing you to damage him as you did previously.
Gooper Blooper appears in episodes 1 and 5 of Ricco Harbor and episode 2 of Noki Bay. Once you have activated the boss battle, the first thing you'll want to do is clean off his face. As you are doing this, he should hit you with his tentacles. Jump out of the way, and use the B button to grab his tentacles. It is only necessary to grab the two inner tentacles to be able to grab his nose. Pull his nose until he becomes pink, and let go to do damage. Rinse and repeat to defeat him.
Wiggler is the boss of episode 3 of Gelato Beach. During this fight, Wiggler will constantly stampede his way along the beach portion of the stage. You'll notice that during this, he will pass by the many small plants growing in the beach. Spray these plants and the sand dunes will grow gigantic in certain arrays, depending on the dune. As wiggler passes by each of these plants, spray them to knock Wiggler over. An arrow will then appear over the portion of Wiggler you need to damage. Ground pound this area do hurt him. Three ground pounds and Wiggler is toast!
Bowser Jr. has some tricks up his sleeve. Mecha Bowser is a gigantic mechanical bowser which shoots rockets out of the barrels on it's chest, and shoots flame out of it's mouth. This boss is fought on a roller coaster riding on a set path around Mecha Bowser. This roller coaster is scattered with missiles, which must be shot at Mecha Bowser to damage him. Remember to spray the bullet bills that approach you from behind, and good luck!
PhantaManta is a paper thing floating silhouette of a manta ray that has covered the entirety of Sirena Beach in electric goop. Talk to the man in front of the sunken hotel to initiate the battle, and immediately begin spraying him. You should be able to make him split into two. As you spray him more and more, he will split more. Now it's just a matter of using an R+A combination to cover as much ground as possible to hit him as many times as possible. As he gets smaller and smaller, his copies will become pink and will turn to attack you. Repeat this strategy til the last one is dead, and you will get your shine sprite!
As you enter the boss arena, King Boo will appear and start using a slot machine. What you want King Boo to land on is the fruit, all other options will get you nowhere. Once King Boo has spit out his fruit, pick up one of the jalapeno peppers he drops and throw it into his mouth. King Boo apparently doesn't like spicy foods, so cool him down by throwing any other fruit in his mouth. Rinse and repeat and King Boo is down!
Bowser is by far the easiest final boss of any Mario game. As you enter his arena, use your hover nozzle on one of the platforms sticking out from Bowser's hot tub. At the peak of your jump, ground pound to destroy it. Repeat this on all five platforms and you've beaten the game! Congratulations!
Thanks for using our guide to beating Super Mario Sunshine Bosses!