The Borg probe was a type of small starship used by the Borg, apparently to scout low-resistance targets. The craft was not as well armed as most larger Borg ships, and was only about 350 meters long. These ships were equipped with transwarp coils. The probe was equally matched by a Starfleet Template:ShipClass in terms of firepower and was shaped as a spearhead (or longigated cubicle, similar to the standard photon torpedo).
The USS Voyager encountered a Borg probe in mid-2375. The crew attempted to disable it by beaming a photon torpedo aboard, but it detonated near the power matrix and destroyed the ship. (VOY: "Dark Frontier")
The script of "Dark Frontier" describes the Borg probe as "a geometric shape we've never seen, and much smaller than the average Borg ship -- about half the size of Voyager."
Of the design, visual effects supervisor Mitch Suskin commented, "We looked at a lot of different shapes. The version which was picked was somewhat bar-of-soap shaped. Once you put Borg things on it, it worked, and you understood it was Borg, but different." (Cinefantastique, Vol. 31, No. 11, p. 33)
The Borg probe is given the name "Interceptor" in the non-canon PC games Star Trek: Armada and Star Trek: Armada II.