Princess Shroob is the ruler of the Shroobs, who planned to attack the Mushroom World of the past. She plans an invasion, and attacks Toad Town first, infesting the town with purple mushrooms, and capturing nearly everyone in it. She then attacked Princess Peach's Castle and redesigned it to resemble a Shroob Castle. However, the real Princess Shroob is her older sister, who has been trapped in the Cobalt Star by Princess Peach. Then younger Princess Shroob captured Princess Peach and took over. She tries everything to get revenge on her sister instead of staying as leader and letting her rot. Her first, and only game is Mario & Luigi: Partners in Time for the Nintendo DS.
She looks like the Shroob version of Princess Peach like Swiggler is a remake of Wiggler. She wears a dark pink dress, white gloves and a silver crown. She sometimes holds a blue grail.