The backbone of the Protoss army is called the Probe. This little robotic worker has multiple roles, one of them being the harvesting of mineral crystals and vespene gas, both essential elements for the Warping In of structures and units. Its other vital role is that of opening stable Warp Rifts so that buildings can be teleported into the Psionic Matrix. What is extremely useful with this method is that once the Warp Rift is opened, the Probe may resume its other tasks without any need to supervise or sustain the wormhole.