Bowser X

Bowser X is an optional boss that appears in Mario & Luigi: Bowser's Inside Story, its 3DS remake, and Mario & Luigi: Dream Team. This upgraded form of Bowser only appears in the Gauntlet in the Challenge Node and the Battle Ring in Pi'illo Castle respectively.

In Mario & Luigi: Bowser's Inside Story, to get to him, the player must beat all X bosses, and then face all the other X bosses in a row before facing Bowser X. He is the only X boss without a color change from the original and is the only boss not mentioned in the Prima Games guide. In Mario & Luigi: Dream Team, he is faced twice: once in normal form alongside Antasma X in his bat form, and again in giant form. He is the second normal X boss faced, and the final giant X boss.

Mario & Luigi: Bowser's Inside Story / Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey
Like all the other X Bosses in the Challenge Node, Bowser X has upgraded stats. He is capable of performing all of the original Bowser's attacks from the battle in Toadley Clinic, as well as three new ones based on more abilities Bowser has learned through the game. However, Bowser X only uses two of his Brawl Attacks (unless Bowser did not rescue Shy Guy Squad). The attacks Bowser X performs during battle are:
 * Punch - A variant of Bowser's fist attack, which is much stronger than the original one. Mario and Luigi must jump to avoid taking damage. Every once in a while, his nostrils smoke out; when this happens, he attacks much quicker than normal but completely misses the punch and jumps over the Bros. Mario and Luigi should not jump during this attack.
 * Flame - Bowser's trademark flame breath attack. It can be avoided by grabbing onto Starlow before Bowser X launches the attack. If the player misses, the attack deals massive damage to the Bros.
 * Goomba Storm - This attack has two phases. At first, Goombas run after Mario and Luigi, while Bowser X sets some of them on fire. After that, the burning Goombas fall from the sky and the Bros. must use the hammer attack to hit them back. They move at a much faster speed than the original.
 * Shy Guy Squad - This attack is similar to Bowser's attack. It can be countered by a timed hammer attack. This variant, however, bounces back onto the rope then back at the Bros. at a slightly faster speed. This can be countered multiple times.
 * Fireball - Bowser X shoots a simple fireball at one of the Bros., which doesn't do much damage, but he continues to execute this attack up to 10 times until countered. The Bros. must hammer the fireball back at Bowser X to damage him. Doing this causes Bowser X to curl up into a ball and head for the upper portion of the screen; there, a rain of fireballs drops from Bowser X at random times. The Bros. must hammer the fireballs when they're directly above. For the final part of this attack, Bowser X (still curled up) attempts to ram himself into one of the Bros., heavily damaging them if not countered. When countered, Bowser X flies off screen, then reappears trying to ram the other Bro.
 * Giant Bowser X - Bowser X grows in size and attacks the Bros. with a barrage of fireballs. One can tell when an oncoming fireball is heading toward one of the Bros. as Bowser will clench his fist upon firing it. The Bros. should jump only when the fireballs head directly toward them, and remain on the ground when the fireball passes overhead; in the remake, all fireballs must be hammered. After Bowser X finishes, he proceeds to chase the Bros. through a series of fiery obstacles; to avoid major damage, the Bros. must jump over said obstacles and head for the two Trampolines waiting at the end, this attack is similar to an attack used by the Dark Star Core.
 * Vacuum - A counter move used every time the player uses a Bros. Attack. Bowser X inhales the used move, making it inaccessible for five turns.
 * Fury - In the 3DS version, when Bowser X's HP is low, he gets the Fury status effect. The instant this happens, he will use a Drumstick to recover all of his HP.

Mario & Luigi: Dream Team
During the first battle against Bowser X, he is accompanied by Antasma X in his bat form in Class 2 of the regular battle ring. Bowser X uses all the same tactics Bowser does for this battle: the first one has him spew purple waves of fire at Mario before launching a bigger flame attack that Mario must jump over. For the second tactic, Bowser rolls up into his shell and chase Mario through the foreground, creating flames that he must avoid while running; the red flames are avoidable by jumping, while the purple ones must be avoided completely. Bowser X's third and final tactic shows him attempting a sliding punch, which Mario must counter with his hammer; before punching, Bowser X may teleport behind Mario to catch him off guard. Unlike the regular battle where Antasma is forcibly popped out of Bowser and they retreat, Bowser X and Antasma X explode upon their defeat.

Bowser X is also fought in Giant Class 5 as a giant boss. This fight is mostly the same as its story equivalent. However, his attacks are slightly stronger and faster, and his stats are increased. He also has slightly different attack patterns, and a turn limit of 6 is given.

Names in other languages
Bowser X Bowser +