NOTE: I realize, that Unicorn was third and not the 2nd Ghost Mechanical Beast of the series, ignoring Minotaur M7. So Minotaur will be made before the years is out.

Unicorn Σ2 was the 3rd Ghost Mechanical Beast Archduke Gorgon lends to Dr. Hell's Army in his fight against Mazinger Z in Episode 71 of the original anime. He was Red, Purple and Greenish blue in color, with the head of a horse and a a single horn and big point ears and mane, human torso and arms, and horse legs, with Wings and a jet pack in the back, which allowed him to fly. Unicorn's powerful wings could create hurricane force winds. It possesses noticeably strong armor that is able to resist some of the most powerful and destructive blows. The horn on its forehead emits electricity in the form of bolts or sparks that can pierce armor and barriers and it possesses three repelling rays on its neck.

Following the battle with Gusios βIII and the damage sustain to the old Pilder, the Photon Power Lab prepares for a three stage plan to Upgrade Z's defense, the combat capability for the Scrander and construction of the new Jet Pilder, also with greater speed, defense and combat capabilities. Meanwhile, the Submarine Fortress Bood sails to Japan, this time with Archduke Gorgon on board, to witness first hand the power of Mazinger Z. As soon the Bood emerges, Unicorn Σ2 is launched on way to the Photon Power Lab, via the city, Aphrodite and Boss Borot are launched to intersect it as work on Z still continue. As soon the two encounter Unicorn, he repels Aphrodite's Rockets with its Repellent rays, and these falls around the Borot – Boss faints and Nuke and Mucha take control, only to be more ineffective than usual. Unicorn zaps Sayaka into unconsciousness and blows Borot with a gust of wing as it takes off to the lab. A Boastful Gorgon celebrates, but Ashura warns him not to do so prematurely.

The lab activates the Energy Shield, Unicorn arrives and slams onto it over and over to weaken it – Koji rushes into the new Jet Pilder as Unicorn breaks in, Mazinger is launched, the two proceeded to fight, Z blasting the right arm off with Photon Optic Beam. Unicorn takes off and proceeds to attack from the air, leaving Z in a disadvantage as the Scrander wasn't ready yet. Looking to his situation, Koji thinks to keep the beast away from the lab, Z runs away with Unicorn on his tail. Unicorn pins Z down with his repellent beams, but Aphrodite and Borot show up – Sayaka uses her rockets to distract the Beast and it rushes towards her, but Borot intersect and blocks its attack, getting impale by the horn. Koji takes its chance and takes off on the Pilder developing into a dogfight, in the meantime, a Contingency of Iron Mask soldiers are sent out to attack the Photon Lab with Ashura leading the charge, as the Lab's defense are out for the count, damaged in the attack, Aphrodite and Borot round up to provide protection. Koji however deals blows to Unicorn as it blast its rocket pack, causing it to be grounded – he reunites with Z and fires Drill Missiles, destroying the Repellent Rays, then cuts his horn off with the Bladed Rocket Punch, hits it with Rust Hurricane and dispatches Unicorn with the Breast of Fire.

Z runs back to the lab and Ashura orders retreat when told, Borot is left set blazing, but Z uses his Ice Beam to turn down the heat, leaving it frozen. Gorgon vows revenge for the destruction of Unicorn after witnessing Mazinger's Power first hand.