The Cytherian probe was a type of probe launched by the Cytherians to find other races and enable them to come to their homeworld, located near the center of the galaxy. One such probe attempted contact with the Argus Array in 2367 but damaged it. When the USS Enterprise arrived to investigate, the probe was able to reprogram Lieutenant Reginald Barclay's brain, briefly enhancing him to bring the ship to the Cytherian homeworld via a subspace distortion. The probe was destroyed with aid from the newly enhanced Barclay after becoming a threat to the Enterprise. (TNG episode: "the Nth Degree")
- More probes can be assumed to exist.