Dark Bowser

Dark Bowser is Bowser's final boss in Mario & Luigi: Bowser's Inside Story.

While the evil Dark Star was gathering DNA from Bowser's body, Mario and Luigi tried to stop it before it succeeded with its goal, the brothers succeeded to defeat it, but it seemed that he already got every piece of DNA that he needed, the only part which was missing were the legs which he gathered by inhaling the Dark Fawful Bug into his stomach, and thus creating a dark version of Bowser. Dark Bowser then covers the whole Mushroom Kingdom into darkness, and Bowser was the only one who could defeat him. Eventually, after being defeated, Bowser then charges up his fists and gives the dark version the final blow.

One of Dark Bowser's attacks is throwing a boulder into the air and blasting it apart, causing rocks to fall out of the sky. Bowser must use his shell to avoid taking damage. However, he must also punch one of the rocks at Dark Bowser, who is charging an attack. When the rock lands in his mouth, it plugs him up & causes his attack to damage him from the inside.

Another attack has him punch Bowser repeatedly. Bowser must counter with his own punch. Then Dark Bowser will jump into the air as a spiked ball and land on Bowser. Bowser must retract into his shell to avoid taking damage. He can then counter attack by quickly throwing a punch at Dark Bowser. Another attack is trapping Bowser in a cage and raising it into the sky. He will then charge up an energy ball. Bowser must try and destroy the cage's lock before he gets hit by the energy ball. After taking enough damage Dark Bowser will fall to the ground, but then gets healed by the ingested Dark Fawful and will grow giant. He will always follow this up by tossing a mixed ball of "Dark Minions" at Bowser, including Goombas, Koopas, Thwomps, Bob-ombs and Bullet Bills. Bowser has to punch him in the stomach so that he spits up Fawful and then inhale him, which Dark Bowser will try to do as well.

When Dark Bowser is incomplete, his speech is halting and written in all katakana. When he inhales Dark Fawful and is completed, he begins to speak in more natural Japanese, with kanji and no pauses.