Princess Shroob

Princess Shroob is the main antagonist of Mario & Luigi: Partners in Time. She is second-in-command of the alien race known as the Shroobs (her older twin sister is the leader), although initially it appears that she is their leader, since the elder Princess Shroob was absent, trapped in the Cobalt Star by Peach. She and her sister set off a full invasion of the Mushroom Kingdom to make it their own.

Mario & Luigi: Partners in Time
Princess Shroob invades the Mushroom Kingdom in the past along with her sister, the Elder Princess Shroob, as their home world was withering. After the Shroobs take hold of Peach's Castle, they find the adult Princess Peach, who had just used Prof. E. Gadd's time machine to visit the past castle. The Elder Princess Shroob attempts to capture her, however Peach uses the Cobalt Star used to power the time machine to imprison the Elder Princess Shroob before shattering, scattering across the Mushroom Kingdom. The younger Princess Shroob then ambushes and captures Peach. She sends a Junior Shrooboid into the time machine and sends to with the last of its power back to the future, where its appearance prompts the adult Mario Bros. to investigate the past via timeholes.

When the assembled baby and adult Mario Bros. ride aboard Baby Bowser's Koopa Cruiser, Princess Shroob is seen in a transmission, largely obscured by shadows. From the newly converted Shroob Castle, she fires a Shroob missile, aiming for the Koopa Cruiser. As the Koopa Cruiser was low on ammo, the missile hits it and leads to a crash landing in Baby Bowser's Castle.

Later on, when the Mario Bros. appears at the Koopaseum, Princess Shroob appears on stage, feeding Princess Peach to Petey Piranha. Princess Shroob then sends the Shrooboid Brat to fight them while she retreats. The Mario Bros. then defeats the Shrooboid Brat, only for Princess Shroob to have a hole broken under them, where they fall into Gritzy Caves.

After Petey Piranha is defeated, the Mario Bros. encounter Peach, where she has a Shroob mushroom attached to her face, who is the Princess Shroob in disguise. They take her back to Princess Peach's Castle in the future. The adult Bowser arrives to kidnap her, believing she is Princess Peach, unknowingly saving the present Peach's Castle from domination by the Shroobs. Bowser brings her to Thwomp Volcano, and after he is defeated by the Mario Bros., the Shroob Mother Ship arrives and captures the disguised Princess Peach. The Mario Bros. follow the disguised Princess Peach into the Shroob Mother Ship, where Princess Shroob reveals herself. She and the Shroobs are poised to defeat them, but is suddenly blasted away by a disguised Kylie Koopa. The Bros. and Kylie Koopa eventually get dropped from the Shroob Mother Ship into Toad Town and Yoshi's Island respectively.

After the Mario Bros. assemble the rest of the scattered shards of the Cobalt Star, they eventually go through a Shroobified Peach's Castle. At the top of the highest tower, they hijack a Shroob Battleship and engage Princess Shroob aboard the Shroob Mother Ship. After they down the Shroob Mother Ship and return downstairs, they witness Princess Shroob emerge from the wreckage. She is furious, declaring Peach useless, the kingdom hers, and the brother's dooms sealed, shouting "Destroy!" repeatedly. The group enters battle.

Princess Shroob fights initially from the protection of her levitating throne, bearing a force field that can be destroyed only by repeatedly jumping. The force field does two attacks each turn and regenerates from de-activation after two turns. Princess Shroob fires laser beams of varying heights. Princess Shroob also has an extended attack sequence that inflicts several status effects. The first part involves sprouting limbs from the throne, where she advances over a brother and fires laser rings directly downwards, which enclose from the outside, forcing rapid jumping to dodge. Failing to avoid this attack causes damage and the trip altered state. After the laser barrage, Princess Shroob has her throne attempt to crush the brother directly. She shakes the mech three times and then either laughs or goes down. If she laughs, the mech delays before dropping. The attack can be countered by the Hammer, and if unsuccessfully blocked causes dizziness.

Once the Mario Bros. destroy her throne, the Shroob Princess employs personal attacks. She always teleports wildly before acting. She can shoot a lone fast energy ball at one brother, stand in the middle of the room and shoot a storm of energy balls, or hover in the air and rain energy balls downwards. Princess Shroob's arm gestures telegraph which brother needs to dodge, either by jump or hammer. All her energy ball attacks can inflict Poison. Princess Shroob's final and most powerful attack is to launching an energy Star that encircles the arena, traveling faster and faster until it strikes a brother, which can cause random stat decrease, or is stomped on. It can alter its speed to catch the group off-guard. If she points straight forward, the star first attacks Mario; if she points downwards, it attacks Luigi. Once Princess Shroob has lost half of her health, she begins to glow red, attacking more frequently and with more power. When the brothers defeat her, Princess Shroob lies battered on the floor. Baby Bowser meanwhile assembles the Cobalt Star using the last piece. As the star suddenly starts to shudder ominously, Princess Shroob crawls to the Mario Bros, and shouts that it is her sister's turn to defeat them now. She then explodes in a characteristic boss fight shower of sparks, as the Elder Princess Shroob gets freed.

Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey
Princess Shroob makes a cameo appearance next to the Elder Princess Shroob during the optional boss fight of the Shroobs in Bowser's Castle, unlike in the original game, only the Elder Princess Shroob is barely seen. Princess Shroob is also mentioned in the Shroobs' profile from the Bowser Jr.'s Journey mode.

Super Mario-kun
Princess Shroob appears in the Mario & Luigi: Partners in Time adaptions in the Super Mario-kun manga, serving the same role as she does in the game.

Super Smash Bros. Ultimate
Princess Shroob appears as an Advanced-level, neutral spirit in Super Smash Bros. Ultimate. The battle to unlock the Princess Shroob spirit is a stamina battle against Princess Peach. After taking a high amount of damage, Peach becomes giant and her attack power increases, which is possibly to act as a reference to her older twin.

Powers and abilities
As the commander of the Shroobs and one of the final bosses of Mario & Luigi: Partners in Time, Princess Shroob is powerful and she often uses the Shroob army to her needs. By herself, she demonstrates various energy abilities, such as throwing energy balls, flying, and controling stars in her boss battle. Princess Shroob also shows technological skills via the use of her throne. In addition, she can disguise herself as Princess Peach to fool the characters, despite the disguise having a Shroob mushroom on her face.

Personality
Being the primary antagonist of Mario & Luigi: Partners in Time, Princess Shroob is a militant conqueror and is shown to be highly aggressive, despite her dialogue mostly being undecipherable. Several examples of her aggressive personality include shooting the Koopa Cruiser down and feeding Princess Peach to Petey Piranha as a source of entertainment to a Shroob audience. In addition, due to her status as the ruler, the Shroob race acts as her loyal subordinates, serving her drinks and always following her commands. She also takes revenge on Peach for capturing her twin sister and imprisoning her in the Cobalt Star by capturing her herself; prior to starting her battle with the Mario Bros., she states that Peach is "useless now", indicating that she had been using Peach for strategic reasons.

Quotes
While Princess Shroob mainly speaks in the Shroob language, the quotes below are her lines translated in-game:


 * "I am Princess Shroob. You interlopers...will be consumed."
 * "NOW YOU'VE DONE IT!"
 * "YOU'RE USELESS NOW, PEACH!"
 * "TIME TO FINISH YOU!"
 * "YOU CANNOT ESCAPE! THIS KINGDOM IS MINE!"
 * "I WILL DESTROY YOU ALL! DESTROY!"
 * "NOW IT'S YOUR TURN... SIS... TER!"

Trivia

 * In the North American version, when the player defeats Princess Shroob, the victory screen appears showing that no Experience Points or coins are awarded. In other versions, the battle screen immediately fades out to the field after the death animation.