Lake Lapcat

Lake Lapcat is a cat-themed archipelago exclusive to the Bowser's Fury campaign of Super Mario 3D World + Bowser's Fury. During the introductory cutscene of the campaign, Mario falls through an M-shaped portal made of black goop, which transports him from the Mushroom Kingdom to Lake Lapcat. It is a colorful, open area primarily inhabited by various colored kittens, including calico kittens and their Oyaneko. To match this theming around cats, nearly all of the elements of Lake Lapcat, including signs, archways, trees, shrubs, flowers, rainbows, and even the sun, include feline features such as fur, tails, and cat ears. Additionally, cat-themed variations of little birds, as well as enemies and bosses that appear in the Super Mario 3D World campaign, can be found throughout the area with the same modifications. However, all of these cat-like enemies function identically across both campaigns, with the exception of Cat Goombas, which are darker and do not dive. Despite this, Cat Bullet Bills retain their homing functionality.

Lake Lapcat is entirely surrounded by black goop that Mario and Bowser Jr. must work to remove throughout the course of the campaign by collecting Cat Shines. In the middle of the lake is the Fury Sun, a large mass of black goop that protects Fury Bowser while he is not active. When Fury Bowser becomes active, the clear daytime sky changes to nighttime during an intense rainstorm, and he shoots Fury Spikes that plunge into the ground and walls, becoming platforms that Mario can jump on and traverse areas differently with. While collecting a Cat Shine during Fury Bowser's rampages forces him to retreat, he can only be directly battled through a power-up unique to Lake Lapcat, the Giga Bell. Three Giga Bells can be found on large pedestals across the archipelago, each of which correspond to a set of four islands that share a similar visual theme.

Islands
Lake Lapcat is split into twelve named islands and various smaller pieces of land surrounding them. Each of the twelve islands contains a lighthouse that is covered in black goop when Mario first encounters it. By collecting any Cat Shine on the island, the goop on its lighthouse is removed and that lighthouse's light dissolves any goop nearby, sometimes allowing access to additional challenges. Every island contains five Cat Shines that are collected through gameplay challenges. On each island, three Cat Shines are obtained through unique challenges (though some are reused between islands), one is obtained by collecting the five Cat Shine Shards around the island, and the last is hidden behind a set of Fury Blocks somewhere on the island that Mario must coax Fury Bowser into attacking to access the Cat Shine.

The twelve islands are split into three major regions of four islands each: the Lakeside region, which contains Fur Step Island, Scamper Shores, Pounce Bounce Isle, and Fort Flaptrap and has a yellow color scheme, the Ruins region, which contains Slipskate Slope, Clawswipe Colosseum, Trickity Tower, and Crisp Climb Castle and has a blue color scheme, and the Wasteland region, which contains Risky Whisker Island, Pipe Path Tower, Roiling Roller Isle, and Mount Magmeow and has a red color scheme. Each of these regions also has a Giga Bell at or near their center, each of which is named after its respective region. Collecting a certain amount of Cat Shines, the number which increases as the game progress, activates these Giga Bells and allows Giga Cat Mario to battle Fury Bowser. While only the Lakeside region is initially available to explore, if Fury Bowser is defeated in battle once, the Ruins region rises from the water and becomes available as well. If he is defeated in battle for the third time, the Wasteland region also appears.

After completing the first "Make the Lighthouse Shine" mission and falling off of Fur Step Island into the land below, it is not accessible again until Giant Bowser has been defeated once and the player sees the credits and returns to gameplay, upon which Mario begins back on Fur Step Island. After this, a new island named Lucky Isle appears in one of five set locations each time Fury Bowser begins rampaging, offering up to five Cat Shines, one from each location.

Cat Shines
In addition to the ones found on the islands themselves, there are also 35 individual Cat Shines scattered around Lake Lapcat as a whole. While they are each counted individually and labeled as being from Lake Lapcat, they are usually found within a certain Giga Bell sector. Some are initially covered in black goo, making them unaccessible until a nearby lighthouse is lit up, removing the goo.

Ruins Giga Bell

 * Ruins Rabbit Plays Tag: Obtained by making contact with a large rabbit that flees from Mario whenever he approaches it.
 * Go with the Floe: Floats through the air and can be reached from the top of a moving ice floe when the two align.
 * Hurry! Slide through the Sky!
 * Dash and Smash in the Clouds
 * Slippery Skirmish
 * Gazing Down at the Islands
 * Hurry! Swim and Slide!
 * Cold Cove Combat
 * Lost Kittens near the Ruins: Obtained by finding three calico kittens located in the Ruins area back to its parent, which sits by the Giga Bell. Cannot be obtained until after the lost kitten Cat Shine in the Lakeside area has been obtained.
 * Lake Rabbit Plays Tag: Obtained by making contact with a large rabbit that flees from Mario whenever he approaches it.
 * Toad Brigade: Stuck under the Slope:Can only be obtained after the main story is completed by finding Yellow Toad. His location is under a part of Slipskate Slope. To find him, the player must fall under the island near the start of the slope, and quickly go to the ledge where Yellow Toad is.
 * Toad Brigade: Cuddly Castaway:Can only be obtained after the main story is completed by finding Banktoad on a small island located within black goop that can be reached using spring objects on other nearby small islands.
 * Plessie Medal Mania

Wasteland Giga Bell

 * Footprint Free-for-all
 * Spin, Scramble, Shine
 * On the Floodgate's Edge:Located atop the end of a large floodgate, some sections of which are made out of Fury Blocks. It can be accessed from Pipe Path Tower.
 * Hurry! Climb the Falls!
 * Gazing Over the Falls
 * Surprise Prizefight
 * Jump and Thump in the Clouds
 * Wasteland Rabbit Plays Tag: Obtained by making contact with a large rabbit that flees from Mario whenever he approaches it.
 * Lost Kittens in the Wasteland: Obtained by finding five calico kittens located in the Wasteland area back to its parent, which sits by the Giga Bell. Cannot be obtained until after the lost kitten Cat Shines in the Lakeside and Ruins areas have been obtained.
 * Shining on a Hidden Isle: Located on a small island surrounded by black goop that Mario can use Plessie's high jump to reach.
 * Hurry! Slip to the Shine!
 * Gazing Down at Lava: Located on a small floating island which circles around above the peak of Mount Magmeow. If Mario climbs all the way to the top of the mountain and waits for the island to arrive, then he may use the Cat Mario form to climb a short wall to the top of the island where the Cat Shine is.
 * Toad Brigade: Hot Pursuit: Can only be obtained after the main story has been completed, at which point Hint Toad appears on Mount Magmeow just below the peak, where a Cat Conkdor is attempting to attack him; if this Conkdor is defeated, then Hint Toad awards Mario with the Cat Shine.
 * Plessie Medal Master

Collectibles
Lake Lapcat features Cat Shines, collectibles that are scattered throughout the kingdom, similarly to Power Stars, Shine Sprites and Power Moons of other games. These shines are used to awaken the power of the Giga Bells once enough have been collected. The lighthouses on each island are cleansed of goop once the first Cat Shine on that island is collected. Five Cat Shine Shards also appear per island, which give a Cat Shine once they are all collected. Plessie Medals appear in various locations on the lake and grant Cat Shines if they are collected fast enough. Coins also appear throughout Lake Lapcat.