Elder Princess Shroob

"FOOLISH MUSHROOM HEADS... YOU MAY HAVE BESTED ME, BUT SHROOBS WILL LIVE ON... ONE DAY, THE SHROOBS WILL DANCE ON THE BURIED REMAINS OF THIS PATHETIC KINGDOM..."

- Elder Princess Shroob

The Elder Princess Shroob, referred to as Princess Shroob in-game, is the overarching antagonist and the penultimate boss of Mario & Luigi: Partners in Time. She is the leader of the Shroobs (her younger twin sister, Princess Shroob, is the second-in-command), an alien race that invaded the Mushroom Kingdom. When Princess Peach, Toadiko and Toadbert time-travelled to Peach's Castle of the past using Prof. E. Gadd's time machine, they met the Shroobs. The Elder Princess Shroob attempted to attack Peach; however, Peach used the power source of the time machine, the Cobalt Star, to trap the Elder Princess Shroob inside. Peach then shattered the star into pieces; however, the younger Princess Shroob was still able to capture Peach and trap her in Shroob Castle.

Mario & Luigi: Partners in Time
Throughout the game, Mario, Luigi, Baby Mario and Baby Luigi collect the various pieces of the Cobalt Star, not knowing that the Elder Princess Shroob is actually trapped inside. When the brothers get to the top of Star Hill, the "spirit of the Cobalt Star" - actually the Elder Princess Shroob in a disguise - appears and speaks to the brothers. It seemed that only Baby Luigi knew, since he was crying when "the spirit of the Cobalt Star" appeared. Various other characters such as Kylie Koopa and Toadbert hinted the fact that she was hiding inside the Cobalt Star, even as early as when the Mario Bros were in Yoob's Belly.

Finally, at the end of the game, after Princess Shroob is defeated, it is revealed that Princess Peach kept the center shard of the Cobalt Star. Peach tells the Mario Bros. that she cannot allow them to repair the Cobalt Star, but before she can explain why, Baby Bowser comes in and steals the last shard, combining it with the five that the heroes had already collected; the Shroob Princess, now enraged over the recent death of her younger sister, turns Baby Bowser into a Shroob mushroom and resumes her original form as Peach explains to the Mario Bros. what had really happened when she had gone back to that time period. Upon resuming her original form, the Elder Princess Shroob promises to kill the Bros. as revenge for her sister's death and then activates the platform they were standing on, engaging them in battle high above Shroob Castle. Notably, she says this in the language of the other characters, the only Shroob in the game who does that.

The Elder Princess Shroob is much stronger than her sister, and commands a fleet of Shroob saucers. Her attacks depend on how many saucers are present; with just one, she can heal herself with a drink that recovers 120 of her HP (80 in non-American versions), or summon a Chain Chomp to attack Mario or Luigi, who must jump over it to avoid damage. With two saucers, she can ride on top of the saucers and fire large energy blasts at the Bros. from the top screen with her left and right claws respectively; The Princess then fires larger orbs at the Bros. from the background, forcing them to jump if the Princess isn't lined up with the top of her throne before being blown from the saucers and landing on the platform, causing a shock-wave that must be jumped over. With three saucers, she can summon a meteorite, with which she attempts to crush the Bros; the targeted bro must whack her with the hammer enough times to make her drop it. Every time more Shroob saucers are summoned, Princess Peach throws a star to the Bros., with which they can knock saucers out of the sky and prevent the Elder Princess Shroob from using some of her attacks. The Bros. can also earn Bros. Items (such as Red Shells and Smash Eggs) from the fallen saucers. Occasionally, she might throw a Super Mushroom to one brother.

The Princess's only move that is always available is a headlong football tackle towards one of the brothers, which must be hammered twice before she relents. If she pauses for a longer while before the tackle, she will stall right before she hits the targeted brother, tricking them into swinging their hammer too early. In all non-American versions of the game, every time the player attacks the Elder Princess Shroob, an exclamation mark appears above her, and she uses this attack against the Bro. who attacked her previously.

Once the Elder Princess Shroob loses half of her health, she activates her crown and morphs into her true form, causing Princess Peach to collapse in fear. The Bros. must defeat this monstrous form to put an end to the Shroob invasion. In this second form, the Elder Princess Shroob has seven parts: four arm tentacles, a group of leg tentacles, a crown, and her main body. While the crown is activated, the head receives only 1 damage from all attacks. To defeat her, the Bros. must destroy the legs to reach the crown, and then deactivate the crown to make the head vulnerable. The tentacles, legs, and crown reactivate 3 turns after they are destroyed.

Each body part has different attacks usually going in the order of head, tentacles, then feet. The head has two attacks; one is to summon up to six Shroob saucers, and then launch a laser ball that hits all of them in a random order, causing them to either catch fire or short-circuit. After a few seconds, they will fall one at a time in the order they were hit. The saucers that are on fire will land on Mario, and the electrified ones will land on Luigi, referencing the brothers' respective Firebrand and Thunderhand abilities in Mario & Luigi: Superstar Saga. This attack is repelled by hammering the saucers at Princess Shroob. For the second attack, she launches a giant purple energy ball to the top screen, and proceeds to launch smaller red and green blasts into it in random order. The giant ball will then land on whichever color blasts the ball absorbed more of. That bro must hammer the ball, to which it will then land on the other bro who must hit it with their hammer.

The tentacles have two attacks; one is to stab the Bros. with her tentacle claws, being telegraphed by a sparkle. This is avoided by jumping depending on which tentacle sparkled, and happens 2 to 4 times a turn. The upper two claws can also be used as a fake-out attack, hitting slightly above the Bros. The second attack has both right and left tentacles slither towards the Bros. at the same time to grab and throw them at the ground, and they must both use their hammers at the correct time to counter them. For the legs, the Elder Princess Shroob backs up and spits 2 to 5 poison gas clouds at the Bros. that must be jumped over. Her legs also have a passive attack at the end of every turn, which causes her legs to sweep across the floor in a circular motion. The Bros. must jump at the same time over and over until the spinning stops. She can do this attack with just two tentacles, or three later on. Her last and rarest attack used by the head after half her HP is depleted requires the legs to be activated. Similar to the head's first attack, she summons six saucers, but she backs up and summons a time hole as well. When all of the saucers are hit, they will be sucked into the time hole and disappear. On a later turn with the legs activated, the time hole will reappear and spit out the saucers in the order they were hit on the other turn.

When the Elder Princess Shroob is defeated, she becomes a Shroob mushroom, although not before gloating that even with her defeat, the Shroobs will ultimately best the Mushroom Kingdom regardless. Mario, Luigi, Baby Mario, and Baby Luigi take it to the present Peach's Castle for it to be analyzed by Professor E. Gadd. However, when they get there, they find Bowser lying unconscious on the floor. The mushroom that was the Elder Princess Shroob comes to life and inserts itself inside Bowser's mouth, fusing with him and creating Shrowser, who instantly regains consciousness and attacks the heroes. Despite being unable to attack Shrowser directly, the heroes prevail and the Shroob threat is eliminated. The characters, after bidding farewell, then return to their own timelines.

Mario & Luigi: Bowser's Inside Story / Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey
The Elder Princess Shroob was one of many Shroobs seen in the cold room of Bowser's Castle during Mario and Luigi's fight with the Shroobs in Mario & Luigi: Bowser's Inside Story. She appears in full view in the background of the battle, as do many other types of Shroobs; outside the battle, the Elder Princess Shroob can still be barely seen, mostly cut off by the top of the screen, while there are fewer of the other Shroobs. The room is overall much smaller than in the battle.

In Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey, the Elder Princess Shroob reappears as a cameo. Princess Shroob is seen next to her, and she is able to be seen more clearly.

Personality
The Elder Princess Shroob appears too briefly for her personality to be explored in-depth, but her short appearance does give some basic traits of the Shroob monarch. The Elder Princess Shroob seems to have cared a lot for her sister and swears her life into avenging Princess Shroob's death: indeed, the Elder Princess Shroob never makes any mention of her own ambitions for power in-game. However, she still seems to have had many of the bad traits Mario villains tend to show. She seems to be deceptive and manipulative, as shown by her convincing the Bros. to repair the Cobalt Star under the guise of it being a 'star sprite': she also does not appear to be particularly appreciative and is highly condescending, as she then responds to this favor by promising to bring death to the Bros and insults them repeatedly in the process, referring to them as "foolish mushroom heads." In addition, in spite of the confidence she shows in her people's abilities during her final speech, she does not visibly show any concern at all for her own people.

Whenever a Shroob saucer performs a task for her, she knocks it away, even for simple tasks like bringing her a drink of Vim; when she turns into a beast, she is even more destructive, shooting down her own saucers so that they hit the Mario Bros. Nonetheless, she has confidence in the success in the invasion of the Shroobs, as evidenced by her last words to the Mario Bros. where she stated that, even with her defeat, the Shroobs will ultimately be victorious over the Mushroom Kingdom, though she is proven wrong afterwards when the Shroobs' weakness is discovered.

Physical appearance
The Elder Princess Shroob resembles her sister, but is bigger and has a hunched body, crooked jaw, green earrings (although she has no ears), pincer hands, and a different suit. In her true form, her limbs are replaced with tentacles and she's grown into a larger size.

Quotes

 * "I LAUGH AT YOU. MUSHROOM HEADS. PATHETIC THINGS."
 * "YOU GATHERED THE COBALT STAR SHARDS WITHOUT EVER GUESSING THE TRUTH! NOW I AM FREE! AND THAT HORRIBLE, HORRIBLE COBALT STAR IS NO MORE!"
 * "I FEAR NOTHING NOW! DO YOU HEAR ME? NOTHING!"
 * "I WILL GIVE YOU A SPECIAL REWARD FOR SETTING ME FREE. YOU WILL LOVE IT."
 * "AND MY SISTER... MY DEAR, SWEET, BEAUTIFUL SISTER... I WILL AVENGE HER!"
 * "FOOLISH MUSHROOM HEADS... YOU MAY HAVE BESTED ME, BUT SHROOBS WILL LIVE ON... ONE DAY, THE SHROOBS WILL DANCE ON THE BURIED REMAINS OF THIS PATHETIC KINGDOM..."

Trivia

 * In the North American version of Mario & Luigi: Partners in Time, the Elder Princess Shroob's crown is given an attack rating, although the crown never actually attacks, as its purpose is to simply protect the princess from damage. In other versions, this has been corrected, as the crown has a Power rating of 0.
 * During her attack where she strikes down her saucers, it is possible for the player to counterattack her attack until her HP reaches zero, and then get killed by the remaining saucers. If this happens, then she does not get defeated, and the player gets a Game Over.
 * In the North American version, the ominous background music plays before the battle against the Elder Princess Shroob begins. In other versions, the music plays when the Elder Princess Shroob appears.
 * When the Elder Princess Shroob becomes a Shroob mushroom, the key item acquisition fanfare plays when Baby Luigi takes it in non-American versions.