Bowser's Lava Lake Keep

Bowser's Lava Lake Keep, or , is the fourth castle level of Super Mario 3D World and its Nintendo Switch port Super Mario 3D World + Bowser's Fury and the eighth and final course in World Castle. It is unlocked via completing Simmering Lava Lake, as well as by having collected 130 Green Stars. This castle is where the seventh and final Sprixie Princess, the red one, is saved. However, Bowser immediately kidnaps all the Sprixie Princesses and builds a Clear Pipe to his own amusement park, World Bowser.

Layout
The level starts in an area with many platforms, Lava Bubbles, and Boomerang Bros., one of which drops a Boomerang Flower upon defeat. A nearby P Switch must be uncovered by kicking a Kick Bomb at the nearby wall hiding it. Hitting the switch results in a nearby bridge being lowered, which gives the player access to a Ka-thunk and Fire Bro-infested area, with the Checkpoint Flag near. After traversing a narrow pathway filled with Lava Bubbles, the player has to defeat two Hammer Bros. in order to reveal a Warp Box that transports the player to a boss fight with Bowser in the Koopa Chase Lv2.

The basic strategy to defeating Bowser is identical to the encounter in Bowser's Highway Showdown: the player must knock the Kick Bombs that he throws back at him by dashing into them. This time, however, the road is littered with hazards, including spike traps and gaps with lava geysers spurting out. Occasionally, the fight travels to a section of the road with a continuous gap in the middle, making it hard to hit the Kick Bombs. Bowser himself spits fire onto the road more often, and also occasionally throws Kick Bombs that are already close to detonation. Additionally, if the player managed to keep a Boomerang Flower, they can use it to deal small amounts of damage to the car.

Bowser is defeated when he is hit nine times, after which a Warp Box brings the player to the area with a red Sprixie Princess and the Goal Pole. However, when the player frees the last princess, Bowser appears and steals all seven once again, even if the player use the two secret warps in World 1 and World 4.

Green Stars

 * Green Star 1: Near the beginning, the first Green Star is above the lava, next to a wall. The only way to get it is to wall jump quickly before touching the lava.
 * Green Star 2: Before activating the P Switch, the Green Star is on top of the drawbridge. The Cat Suit is required to obtain it, although it is possible to reach it by wall jumping between the unactivated bridge and the wall with perfect timing.
 * Green Star 3: After the checkpoint, the Green Star is floating above the lava, and can only be reached by a Boomerang from a Boomerang Flower.

Stamp

 * After the first Green Star, the player has to Wall Jump their way up above the P Switch to get the stamp. The stamp is Boomerang Mario.

Names in other languages
Bowsers Schloss im Lavasee