“YOU INTERLOPERS... WILL BE CONSUMED!”
Princess Shroob is the main antagonist of the game Mario & Luigi: Partners in Time. She is second in command of the alien race known as the Shroobs, (her older sister is the leader) although initially it appears that she is their leader. She set off a full invasion of the Mushroom Kingdom to make it their own.
 Mario & Luigi: Partners in Time
Princess Shroob had invaded the Mushroom Kingdom along with her sister Elder Princess Shroob because Planet Shroob was withering. After the Shroobs manage to get inside Princess Peach's Castle, they find Princess Peach, who had traveled back in time with E. Gadd's Time Machine. They attempt to capture her, but before they can, Peach uses the Cobalt Star to imprison Elder Princess Shroob and scatters the shards of the Cobalt Star. After that, the younger Princess Shroob manages to capture Peach.
In Baby Bowser's Koopa Cruiser, Princess Shroob is seen in a transmission, however she remains hidden in the shadows. From Shroob Castle, she fires a missile, aiming for the Koopa Cruiser. Since the Koopa Cruiser was low on ammo, the missile hits the airship and it crashes in Baby Bowser's Castle.Later on, in the Koopaseum, Princess Shroob appears on stage to celebrate the conquest of the Mushroom Kingdom by feeding Princess Peach to Petey Piranha. However, Mario, Luigi, Baby Mario, and Baby Luigi interupt her by getting onstage. Princess Shroob then orders the Shrooboid Brat to defeat them. Mario and company eventually defeat the Shrooboid Brat, but after the fight, Princess Shroob breaks a hole under the heroes, and they fall to the underground.
After falling underground, Mario and company set out to rescue Peach in Gritzy Caves. When they reach her, she has a Shroob Mushroom attached to her face. They take her back to Princess Peach's Castle in the future. This princess was actually Princess Shroob, and fools everyone, even Bowser, who kidnaps her believing she is Princess Peach. Bowser brings her to Thwomp Volcano, and after he is defeated by Mario and company, the Shroob Mothership arrives and captures the princess. Mario, Luigi, and their younger selves follow, still believing she is Princess Peach. Once they finally reach the fake Princess Peach, Princess Shroob reveals herself. She is about to get rid of them, but is blasted away by a disguised Kylie Koopa. This victory is short lived when she recovers and then drops Mario and his friends off of the Shroob Mothership.
The four Mario Bros. eventually make their way through a Shroobified Peach's Castle, hijack a Shroob Battleship and engage the Shroob Princess in a dogfight with the Shroob Mothership. After blasting the Shroob Mothership out of the sky the Princess emerges from the wreckage. She appears to have gone mad, declaring Peach useless, the kingdom hers, and that she will destroy them all, shouting "Destroy!" several times. She then enters battle with them.
Entering the battle, she is protected by a levitating force shield that can only be destroyed by jumps. In it she either fires lasers where it is NOT a good idea to for both to jump at the same time unless both pointers are pointed to the ground. The player needs to see which lasers are pointed up or down to avoid. The second attack is to turn her forcefield into a giant spider mech and then jumps onto one of the bros, with the force shield looming overhead. She then shoots lasers onto the brothers that travel straight down and then enclose on the bro., though this can be countered by jumping. Failing to avoid this attack will cause a small amount of damage and is capable of knocking the target off-balance. Then she attempts to sit on the brother. She will shake the mech three times and then either laugh or go straight down. If she laughs, then the mech will delay before crushing the target. This can be countered by Hammer. This attack can cause Confusion.
After she is out of the mech or rather forced out, she has a couple more attacks. She always teleports madly before using an attack. One attack is to shoot one fast laser ball at a brother. The brothers have to jump. Another is standing in the middle then shooting multiple balls requiring a jump after the other. If she swings her right arm towards Luigi, Mario has to jump then Luigi or the babies, and if she swings her left arm towards Mario, Luigi has to jump, then Mario. Another is to stand above the brothers and throw an energy ball down. If she shoots with her right arm, it is to Luigi, and if she shoots with her left, it is to Mario. It can be countered with the hammer. All of these energy balls can cause Poison. Finally, the last attack is to throw an energy Star that goes around faster and faster and won't stop until it either hits, which can cause random stat decrease, or is stepped on. It eventually goes slower after a while and may go faster again. If she is pointing straight forward, it's to Mario and if pointing down, it's to Luigi.
Once she gets to the halfway point (damage-wise), she glows red, gets stronger, and uses multiple attacks in one turn. Also, the force field does two attacks each turn and regenerates in two turns. The force field can be destroyed or disabled by using the Copy Flower.
After beating the princess, she lies on the floor, near-death. When Baby Bowser puts together the Cobalt Star, she crawls to where the Mario brothers are and shouts that it is her sister's turn now to fight them. She then dies and, like previous bosses, brilliantly explodes.
The Cobalt Star shards are located in many places that Princess Shroob should have been aware of, such as the Vim Factory. It is unknown why she did not attempt to have the Cobalt Star restored and bring her sister back to power.
 Super Mario-Kun
Princess Shroob appears in the Mario & Luigi: Partners in Time adaptions in the Super Mario-Kun, serving the same role as she does in the game.
 Powers and Abilities
Princess Shroob is a formidable foe. Her source of power is unknown, though she demonstrates various energy abilities. Among those enable Princess Shroob to throw energy balls, fly, teleport, and control Stars. Princess Shroob also shows technological skills via the use of her throne. She also seems to be a great Master (Or in her case, Mistress) of disguise as she had everyone fooled into making her think she was the real Princess Peach.
The Princess is shown to have a vindictive personality and takes joy in the pain of others, as shown when she laughs when the Koopa Cruiser is shot down and how she mercilessly feeds Princess Peach to Petey Piranha (though feeding the Princess to the monstrous Piranha Plant could have been just for show, as she had Peach spat back up, meaning she saw usefulness in the Princess). She kept Peach unharmed for the majority of the game because she needed her in order to take over the Mushroom Kingdom in the future, and even destroy the Mario bros (And possibly because she believed Peach knew where the Last Cobalt Shard was). She seems to have a vengeful side, as when Mario, Luigi, and their infant selves destroyed her Mothership, Princess Shroob grew insane and attacked in hopes of destroying them. Although she has a big sister who cares about her, she didn't seem to bother looking for the cobalt shards, though it's possible she had them guarded and wanted to wait until the Kingdom was fully conquered before freeing her sister. Princess Shroob seems to care more about her people than Elder Princess Shroob does.
 Names in Other Languages