Shroob

The Shroobs are a race of aliens from the Shroob Planet that appear in Mario & Luigi: Partners in Time and serve as the main antagonists. The Shroobs invaded the Mushroom Kingdom when Mario and Luigi were babies. They are a purple, mushroom-like species ruled by Princess Shroob and her older sister. Their name is a corruption of the shortened word for mushroom, "shroom."

They possess very advanced technology, such as ray guns and a massive fleet of flying saucers, powered by the vim of Toads, which is collected by capturing the Toads and draining the vim through the Shroobs' Tree Network, all leading to the Vim Factory. The saucers are capable of shooting energy bolts that turn people into Shroob Mushrooms, as well as causing devastating damage to buildings. When invading the Mushroom Kingdom the Shroobs seemingly have everything laid out in advance so that they could both protect vital operations and invade enemy regions at the same time, suggesting they are very intelligent and possess a complex military.

Appearance
The Shroobs are dark purple mushroom-shaped creature with bluish-white spots at the top, have very stubby bodies and limbs, have hands with pincers at the ends, have gaping mouths with a pair of fangs on the top, and have black eyes with red pupils.

Mario & Luigi: Partners in Time
According to the prologue of the game, the Shroobs invaded the Mushroom Kingdom because their home planet is dying.