Fury Bowser

Fury Bowser is a form that Bowser takes in the Bowser's Fury campaign of Super Mario 3D World + Bowser's Fury. In this form, Bowser becomes a gargantuan , being one of the largest physical forms he has ever taken. Similarly to Black Bowser from Paper Mario: Color Splash, Bowser becomes corrupted by black paint, which causes his skin to become entirely black in color, complete with glowing yellow eyes without pupils. In contrast, his hair glows a bright red, while the center of his carapace and the tips of his shell spikes glow yellow and red. It is implied by Bowser Jr.'s paintings, in the credits and when Mario first encounters him, that the form was unintentionally caused by Bowser Jr. painting his father black and angering him.

In comparison to his normal self, his body is much larger than his head, his tail is somewhat longer, he has more spikes on his arm bands, and he has more defined pectoral muscles; the latter trait is shared by Bowser's appearances in the Super Smash Bros. series. Compared to Bowser's normal roar and even Dry Bowser's roar, Fury Bowser's roar is more realistic-sounding, sounding deeper and almost demonic, and has a reverberating echo effect to it.

Behavior
Typically, Fury Bowser is found sleeping in the middle of Lake Lapcat, hiding his whole body inside the Fury Sun (a spiky blob of goo that resembles Bowser's Spike Ball form in Mario & Luigi: Bowser's Inside Story and the Super Mario Galaxy games, as well as the spiky shells he throws in his Super Mario Odyssey battles), which slowly rises from the ground. He usually awakens at intervals of roughly six minutes, but using the Bowser amiibo in the game causes him to appear instantly. His awakening is foreshadowed by the current music changing, and a small rainstorm starting. After a few moments, Fury Bowser will quickly launch into the air as the screen becomes completely white. This transition changes the clear daytime sky of Lake Lapcat to nighttime during a torrential storm.

Once awake, Fury Bowser will land at a location near Mario and begin rampaging. During his rampage, many spike-shaped platforms are launched into set locations on the different islands of Lake Lapcat. Some platforms have Mushroom Trampolines on them, and many can be used by Mario to scale platforms more quickly. Several large land masses of a similar material with Dash Panels will rise from the water, and they can be used by Plessie to move faster and cross gaps of goop. Large, gold blocks that resemble Moon Rocks and usually have ? Blocks containing coins above them also appear.

During Fury Bowser's rampage, he will target Mario with large beams of fire at Mario, During Fury Bowser's rampage, he will target Mario with large beams of fire, which will destroy the spike-shaped platforms and gold blocks upon contact (the latter leaving behind coins). These fire beams will sweep across Lake Lapcat with a very long range, but can be avoided by hiding behind walls or the other objects spawned during the rampage. Additionally, this fire is the only thing capable of destroying Fury Blocks; to show this, the Bowser emblems on the blocks glow red during the rampage.

Throughout the rampage, meteors fall around the entirety of the lake and leave behind small circles of lava where they land, which will disappear after enough time or if Fury Bowser stops rampaging. All kittens and calico cat parents on the lake turn into Fury Cats for the duration of the rampage.

After a while, or if the player collects a Cat Shine, Fury Bowser stops attacking and goes back into his slumber. The sky will change back to calm daylight, all objects summoned during his rampage will disappear, and all Fury Cats will return to normal. If his rampage is ended by collecting a Cat Shine, a nearby lighthouse will either begin to shine or shine brighter than before, and this light damages Fury Bowser slightly. However, it is impossible to defeat Fury Bowser by only collecting Cat Shines, due to the damage stopping once he reaches one point of health.

Battle
If Mario has collected enough Cat Shines to awaken the Giga Bells, then they will become active while Fury Bowser is awake, allowing Mario to obtain them. After Mario obtains a Giga Bell and becomes Giga Cat Mario, a boss battle against Fury Bowser occurs; this happens multiple times throughout the game. Bowser uses several different attacks during these fights. He may use his fire breath, jump up and try to crush Mario, or dig into the ground and cause spikes to rain out. In later fights, he gains additional attacks such as breathing a ring of huge fireballs, summoning giant Kick Bombs (which can be launched back at him to make him flip over and enter his shell, leaving him vulnerable to a Ground Pound before he recovers), and entering his shell before rolling towards Mario on his side. If Bowser attempts to crush Mario, then he will enter his shell and aim at Mario, with a red circle appearing in the place he is set to land; once he does land, a shockwave of fire emerges from him. Mario can then Ground Pound his vulnerable carapace before he recovers to damage him. In later battles, Bowser repeats this attack multiple times in quick succession before he becomes vulnerable. If Bowser chooses to drop spikes, which he usually does at the start of later battles, then red markers show where they will land on the ground. After they land, Mario can pick them up and throw them, and if one makes contact with Bowser, then he will enter his shell and flip onto his back, making him temporarily vulnerable to Ground Pounds. Mario can alternatively damage Bowser by claw swiping him, though this deals less damage than Ground Pounding him when he is vulnerable does. A health bar in red is above Bowser and shows how much remaining health he has; it takes a total of six Ground Pounds to deplete his health bar on the first stage. Though battling him as Giga Cat Mario is the most effective way to deplete his health, a small amount of it will also deplete when Mario collects a Cat Shine and lights up a lighthouse with it while Fury Bowser is active. However, defeating him without becoming Giga Cat Mario is not possible since lighthouses never deal enough damage to bring his health below one. After enough of Bowser's health bar has been depleted, Bowser will be heavily knocked back and fall to the ground, seemingly unconscious. What happens after this depends on whether his health was fully depleted or not; if it was not, then Bowser will get back up, shake his head, and return to the Fury Sun, while if it was, then he will glow brighter and brighter until a massive explosion occurs, causing him to fly upwards in his shell from the blast and hit the water, before sinking back down. This reveals the next islands. When Bowser's health reaches zero in the final Giga Cat Mario fight, he expels the black paint from his mouth before glowing, and then is engulfed in an even larger explosion. Bowser Jr. then approaches him, at which point he rises back up with his regular appearance, albeit much larger (slightly smaller than Fury Bowser) and with glowing white eyes that lack pupils, causing Bowser Jr. to flee. Bowser then traps all three of the Giga Bells in a large crystal ball, and the final boss battle begins.

Later in the game, Fury Bowser's behavior and the color of the sky both change, depending on how many times he is beaten by Giga Cat Mario. Initially, the sky is black, and Bowser stays for a few minutes, or until a Cat Shine is collected. After the second time he is beaten, the sky is a slight red, and Bowser stays much longer. After the third time, the sky is much more red, and Bowser stays until another Cat Shine is collected, as he no longer retreats on his own. When there are only three Cat Shines left until the final battle, Fury Bowser cannot be sent into slumber, forcing the player to collect the remaining three while he is still attacking.

If Bowser's Fury is played after Super Bowser has been defeated once, Fury Bowser will be on either the first or second stage of attack, and the Giga Bells always have no black paint on them, allowing the player to fight Bowser whenever he appears.

Once 100% completion has been achieved by collecting all one hundred Cat Shines and then defeating the final boss again, the red and yellow parts of Fury Bowser are changed to a bright white, and the health bar that appears during battle changes from red to blue. He will also always start battles on maximum health, regardless of if his health has been depleted by collecting Cat Shines earlier.

Trivia

 * Fury Bowser bears a resemblance to Bowser's appearance when using his Mega Strike in Mario Strikers Charged.
 * Fury Bowser and the material in his surroundings resemble, a typically dark fluid that can form spikes when influenced by a magnetic field.