"Dominion military technology grows more sophisticated by the day, and a good example is our new cyclone. This innovative design combines speed and lethality in an efficient package. Originally designed as a robotic vehicle, the cyclone evolved over several iterations to become a human-piloted mech. The reason: even the most highly evolved AI cannot match the unpredictive creativity of a human driver."
To keep personnel out of harm's way,  the Terran Dominion developed the cyclone, a mobile assault drone armed with twin Typhoon missile pods that engage air and ground threats. The cyclone also features a sophisticated lock-on system, which allows it to concentrate fire on an enemy while on the move. Originally designed as a robotic vehicle, the cyclone evolved over several iterations to become a terran-piloted vehicle, due to the creativity of humans (or, as some would call it, insanity), that AIs cannot match. Cyclones are outfitted with all-terrain treads, clutchless transmission and an advanced target acquisition array.
The cyclone is a fast mechanical unit, able to focus on single enemy units and use its ranged attack on them while moving. It moves at the same speed as the protossstalker. It is intended as an early mechanical option for harassment. Stalkers equipped with blink are a good counter to the unit. In its current state, the cyclone is a front-line anti-armored damage dealer.
Using the cyclone to its full potential and reacting to it well are both heavily dependent on micro. The unit works similarly to the diamondback from the Wings of Liberty campaign.
The cyclone used to be able to attack air units from the outset. This was changed so that the cyclone could only attack ground units, but could be upgraded to attack air ones. This was then reverted back to its original state.
During the beta, due to the cyclone's reasonable speed, range, and damage against all unit types, it was not uncommon to see armies almost exclusively consisting of cyclones. Blizzard made adjustments to the unit to ensure that they would not be the only unit needed in a terran army composition. The initial upgrade was researched at the tech lab, and required a fusion core to access.
Lock on originally dealt 300 damage over 30 seconds for ground targets, and
240 damage over 20 seconds against air targets.
As of Patch 3.8.0, major changes were made to the Cyclone. The role was changed to a rapid attacker, and its attack speed was increased while its damage was increased. The "Mag-Field Accelerator" upgrade has been removed, and replaced with Mag-Field Launcher upgrade. By default the air attack of the cyclone was removed, but the lock on ability was made usable against air units and structures, though was no longer autocast. Mag-Field Launchers was removed in the next balance update.
The cyclone's lock on damage is increased to 400 damage against ground targets (+400 against armored), and 400 damage against air targets (+400 against armored). Legacy of the Void multiplayer. Removed with Patch 3.8.0.
Increases cyclone's lock on damage from 500 to 750. Co-op Missions.