Elder Princess Shroob

Elder Princess Shroob is the central antagonist of Mario & Luigi: Partners in Time. She is Princess Shroob's older twin sister, and the leader of all Shroobs. She is the final boss in the game and she is fought in three different forms.

Elder Princess Shroob has cared a lot for her sister and even sweared her life to revenge Princess Shroob's death. Oddly, she shows no concern at all for her own people. Whenever a Shroob performs a task for her, she slams it, even for simple task. She also shoots down her own spaceships so that they will crash on the Mario Bros, thus, killing the pilots.

She wears a crown that has magic power. It has the ability to make her change forms and protect her. When her crow shines, she is invulnerable to any attacks. However her crown can be attacked and can stop shinning after taking enough damage.

Biography
When Princess Peach came to the past Princess Peach's Castle, she met the Shroobs. Elder Princess Shroob attempted to attack Peach; however, Peach used the power of the Time Machine, the Cobalt Star, to trap the Elder Princess Shroob inside. She then shattered it. Mario, Luigi, Baby Mario and Baby Luigi collect 5 of the pieces of the Cobalt Star, not knowing that Elder Princess Shroob is actually trapped inside.

Elder Princess Shroob does not appear until the very end. After Princess Shroob is defeated, it is revealed that Princess Peach kept the center shard of the Cobalt Star. Peach states, however, that she cannot allow the Cobalt Star to regain its original form. Before she can explain, Baby Bowser comes in and steals the last shard, combining it with the five that the heroes had already collected, causing Elder Princess Shroob to come back to life. The baby and adult brothers then fight Elder Princess Shroob on a platform high in the air.

After taking a lot of damage she activates her crown and morphs into a hideous beast. In this form she is about four times her original size and has four arm tentacles and a group of leg tentacles. Once defeated, she turns back into her true self and then turns into purple Mushroom. Baby Luig decides to keep it.

The Mario Bros. and Peach then come back to the present Peach's Castle, where they find Bowser's unconscious body. The purple Mushroom from Baby Luigi's pocket suddenly floats up and goes right into Bowser's mouth. Bowser then gets possessed by Elder Princess Shroob. She appears as a ghost, in her beast form, floating above Bowser. The Mario bros. then defeat them, making Elder Princess Shroob's ghost disapear and causes Bowser lose his power.

Triva

 * In Mario & Luigi: Bowser's Inside Story, she can be seen frozen in the background while fighting the Shroobs in Bowser's Castle.