Dark Star

"It was not benevolent. It was a frightful star that hid a great evil."

- Princess Peach

The Dark Star is an artifact featured prominently in Mario & Luigi: Bowser's Inside Story. Long before the time of the game, it was discovered by Toad archaeologists. It attacked the kingdom, and was sealed away by the Star Sprites. It was said that if someone evil broke the seal on the Dark Star and allowed it to attack the kingdom once again, the evil entity would receive enormous power. Along with Fawful, they are the main antagonists of the game.

Mario & Luigi: Bowser's Inside Story
During the events of Bowser's Inside Story, the Dark Star was stolen by Fawful in order to fulfill his plans. He uses its power to barricade the front door to Peach's Castle allowing him to use it as a stronghold during the game. Mario and Luigi eventually use the Miracle Cure to destroy the barrier. He also kidnapped Princess Peach in order to break its seal. When Bowser confronts Fawful and Midbus near the end of the game, the Dark Star escapes from the machine that Fawful has been using to drain its power. While Bowser is distracted fighting Blizzard Midbus, Fawful absorbs some of the Dark Star's power and is converted to Dark Fawful. He flies off in search of the missing star. However, while he is gone, the Dark Star returns and invades Bowser's body. Thus, Mario and Luigi venture to the final unexplored area of Bowser's body, the Airway. Here, they discover the Dark Star absorbing pieces of Bowser's DNA. They attempt to capture it several times, but each time it escapes using one of Bowser's powers: punching, breathing fire, and the body slam. Starlow theorizes that it is somehow incorporating Bowser's DNA into its own body, apparently interested in Bowser's massive strength and other abilities. Eventually, the Mario Bros. confront Dark Star at the very back of the Airway. They attempt to destroy it, but it simply escapes from Bowser's body. Outside, it transforms into an apparition of Dark Bowser and escapes, freeing Bowser from the room he was trapped in.

Later, when Bowser defeats Dark Fawful, he becomes a small blob of dark power, the Dark Fawful Bug, and escapes. The still incomplete Dark Bowser absorbs Fawful and uses the power he took to complete his body.

The Dark Star's final appearance is during the final battle. After Bowser deals critical damage to Dark Bowser, what remains of Fawful heals him fully and causes him to double in size. At this point, Bowser attacks Dark Bowser's belly, causing him to expel Dark Fawful. Bowser absorbs Dark Fawful for the Mario bros. to handle. Here, he transforms into a giant insectoid mass of dark power, still with his manic grin and now crimson eyes. His only weakness is the Dark Star Core, which sits on an antenna high above his head. As with the final bosses in the previous two games, Mario and Luigi must progressively disable the different parts of Dark Fawful before attacking this weakness. It is likely that it still has a distinct intelligence from Fawful's, since he is visibly displeased whenever it decides to flee. It is eventually destroyed along with Dark Bowser.

Battle
In battle, the Dark Star can not usually be damaged. To expose its vulnerability, the Mario Bros. must destroy the Dark Satellmites that surround it. With sufficient damage, the Dark Satellmites will use a Kamikaze attack that consists of throwing a bomb at one Mario brother, and throwing their own body at the other. Ordinarily, both will miss, but either brother can attack the projectile launched at him. If the bomb is attacked, it will explode, doing damage to either Mario or Luigi. If the Satellmite is attacked, it will be knocked flying into the Dark Star. After being hit in such a way twice, the Star will become vulnerable and immobile for a turn.

Attacks
One of the Dark Star's attacks consists of it splitting into five as a thick fog fills the battlefield. Each Dark Star then flies slowly at Mario or Luigi, vanishing into the fog as it draws near. Mario and Luigi must then counter this attack by using their hammers on the hidden Stars about 5 seconds after they disappear.

In another attack, the Dark Star will shine a bright light at Mario and Luigi, causing their shadows to come to life. The shadows will then move in a circle around the Dark Star, which will attack them with beams of electricity. The Mario Bros. must jump to avoid the electricity that the Dark Star shoots, as any damage done to the shadows will hurt the real Mario Bros. as well.

The Dark Star may also send red and green energy balls into the air. It will then fly through these balls in order, sending them at the correspondingly colored Mario Bro. They may be avoided by jumping.

When the Dark Star is immobilized, he will shoot out a simple laser at Mario or Luigi, depending on who attacked him.

After receiving sufficient damage, the Dark Star will use a laser attack that fills up the entire touch screen. Starlow will appear just before this attack activates, suggesting that Mario and Luigi grab on to her. When they do so, Starlow will fly up in the air (top screen) therefore avoiding the attack. After the attack is through, the Dark Star will look up and attempt to ram into Starlow. The bros. must release their hold on Starlow to avoid making contact with the Dark Star. This attack deals massive damage and may also inflict the Poison status.

Just before it is defeated, the Dark Star will use a vacuum attack on both Mario and Luigi. This must be countered by pressing A and B repeatedly or the brothers will take massive damage. After it uses this attack, the Dark Star is defeated.

Dark Star X
Dark Star X is the sixth boss class located in the Gauntlet, which is inside the Challenge Node. It is the second-strongest boss in the game (after Bowser X). To start, 2500 coins must be paid to battle Dark Star X. The bros. have up to 12 turns to destroy Dark Star X. If the player defeats it, he or she will unlock Class 7, where he/she will fight all previous classes, including the Dark Star X, and Bowser X.

During the battle, Dark Star X is similar to the original Dark Star, just tougher and with a red and blue color scheme.

Some changes are that the Dark Satellmites X's energy beams travel and Kamikaze attacks move faster, just as the Dark Star's clones do; there are also always seven clones. When the bros' shadows come to life, they always split in two, something the original Star only did when it had been weakened.

Trivia

 * Dark Star's beam attack is similar to R.O.B.'s Final Smash.
 * Along with Fawful, they are the only main villans in the Mario & Luigi games that did not posses Bowser. Instead, the Dark Star "copied" him.
 * The Dark Star's huge laser attack is the only one of the bottom screen filling attacks that the player needs to grab on to Starlow to avoid in the game that has two parts. It also is the only one that the player cannot hang on to Starlow as long as they want after the attack is done, because the Dark Star would ram them.
 * It's possible that the Dark Star is somehow related to the Shroobs. They both have the same color scheme, they're affiliated with purple smoke, and when Dark Bowser is formed, he has the same kind of eyes that they do, black irises with red pupils. The Dark Star may very well be the Shroobified version of a Star Sprite.
 * Also, The Elder Princess Shroob swore vengence and destruction upon the Mushroom Kingdom before dying. The Shroobs may have left the Dark Star there as a back-up plan for carrying out said vengence.