Shroob saucer

Shroob UFOs are the Shroobs' alien spaceships that they use for travel from place to place. These spaceships are small; however, they can shoot powerful plasma beams. Shroob UFOS are powered by Swiggler, the bio-mechanical creature that the alien Shroobs created. In the final part of the battle against the Elder Shrooboid, there is a special UFO with a timer, and if the timer hits 0, the UFO will instanly defeat the four Mario Bros.

The UFOs only appear in Mario & Luigi: Partners in Time.