Megalon tumbled to the ground, having been struck by his foe. As the Seatopian deity attempted to return to his feet, his opponent shrieked with evil glee, smacking its clamp-like claws together.

Spyler attacked again, planting his spiked foot into Megalon's gut.

Gigan swung his right scythe at the bizarre creature he was facing. Wargilgar managed to avoid the attack and lunged forward, snapping at Gigan's face with his claws. The cyborg jumped back and fired off a blast of his crimson cluster beam. Wargilgar screeched as explosions went off around his head, driving him back. Gigan advanced, but Wargilgar opened his beak and a double-barreled cannon emerged from within, aiming directly at his foe. Wargilgar spat out a blast, striking Gigan in the chest. Gigan recoiled and Wargilgar leapt forward, tackling him to the ground.

The two pairs of monsters had been warring for hours. The forces of Star Hunter Nebula M and Seatopia had once again united against mankind and sent their monsters - Gigan and Megalon - to destroy the Earth. But as the two titans marched across Japan, they came across another pair of creatures: the Terro-Beasts, Spyler and Wargilgar. Having been sent by the Garoga Empire for the same purpose, the alien beasts were on a rampage of their own. The creatures' respective masters would not stand for this intrusion, and each gave their monsters the order to destroy the others!

Spyler shrieked as Megalon assaulted him with his drills. Megalon wailed on the bulky creature with his metallic limbs again and again, intent on doing as much damage as possible. He had no intention of giving his opponent another opening to attack. In a move of desperation, Spyler threw open his arms and released a series of blinding flashes of light from the knobs on his chest. Megalon shrieked as the light burned his compound eyes, throwing his arms up to protect them and backing away. Spyler charged, but Megalon recovered soon enough and fired a bolt of yellow lightning from his horn, striking the Terro-Beast in the face and knocking him to the ground.

Gigan cried out as Wargilgar's searing flames scorched his body. The cyborg quickly took to the sky, circling around and slamming into Wargilgar from behind. As the insect-like Terro-Beast stumbled forward, Gigan turned around and flew directly for him. Wargilgar screeched as Gigan's buzzsaw gashed against his face, knocking him backward. But when Gigan tried the tactic again, Wargilgar was quick to react, extending his mouth cannon and firing a blast that struck Gigan directly in his visor. Shrieking wildly, Gigan spun out of control and plummeted to the ground, crashing with a thud.

Spyler threw Megalon to the dirt, but the giant beetle was back on his feet in an instant. Spitting out a sphere of napalm, Megalon struck Spyler in the chest with it, knocking him onto his back with the resulting explosion. Before Spyler could recover, Megalon strafed his body with another lightning blast, eliciting a shriek of pain. But just as Megalon advanced on his foe, something exploded against the back of his skull, nearly knocking him off his feet. Megalon turned just in time to have Wargilgar's claw smash into his face. Spyler got to his feet. Gigan was still down. Slowly getting to his feet, Megalon realized he had to fight both Terro-Beasts alone.

Wargilgar charged, readying his pincers. Megalon flexed his arms and did the same. The two crashed together, attacking each other with their weapon-tipped arms. Wargilgar bit down on Megalon's neck with his mandibles, causing the beetle god to wildly wave his arms around, battering Wargilgar with his drills. The Terro-Beast was forced away, allowing Spyler to slam into Megalon from the side. Megalon was flung to the ground by the impact as his foes regrouped and attacked together. Spyler slammed his clamp-like claws down on Megalon's back as Wargilgar grabbed hold of his horn. Charging the horn with electricity, Megalon dislodged Wargilgar in a burst of sparks and stood up, decking Spyler across the face with his right arm. Wargilgar attacked again, once again snatching Megalon's horn in his claws. Pulling Megalon down, Wargilgar set him up for a body slam from Spyler. With a sickening snap, Megalon's horn broke away as Spyler crashed into him.

Megalon's agonized screech caught Gigan's attention, getting him to focus and rejoin the battle. Aiming his arm at Spyler, he fired off his capture cables. They quickly wrapped around Spyler's arm and, with an angry cry, Gigan pulled the Terro-Beast away from his ally.

Blood continued to drip from the stump where Megalon's horn once was as he and Wargilgar continued to struggle. The blue and orange beast dodged a blow from one of Megalon's drills and shoved him away. Megalon responded by spewing napalm at his foe, blasting him back.

Spyler tried to pull himself away, but Gigan's cables were wrapped too tightly. The cyborg began reeling his opponent in, starting up his chest-mounted buzzsaw as he did so. Spyler tugged, but couldn't break free. The bulbous creature unleashed more flashes of light from his chest, blinding Gigan momentarily. Spyler snatched the cables and yanked on them, trying to pull Gigan off his feet.

Wargilgar screamed as another of Megalon's orbs exploded against his flesh. The Terro-Beast was ready for the next use of the tactic; when Megalon's mandibles opened next, he fired off his mouth cannon, blasting into Megalon's throat. As the insect deity choked and gurgled, his drill-hands at his mouth, Wargilgar stepped forward and unleashed his hellish flames at his opponent. Megalon cried out as the fires scorched his skin.

Spyler tugged on Gigan's cables, bringing him closer. The cyborg refused to fall, screeching in defiance at the Terro-Beast. Spyler began to fire more bursts of light, but Gigan quickly fired a blast of his cluster beam, striking Spyler in the face. With his foe distracted, Gigan yanked hard, causing Spyler to stumble forward. Bringing his other arm up, Gigan thrust it forward, sliding his blade into Spyler's chest. The Terro-Beast shrieked as Gigan's scythe pierced his flesh. Gigan withdrew his blade, and as Spyler clutched at his injury, the cyborg fired a blast of his cluster beam into the wound. Seconds after the red energy entered his body, Spyler squawked in agony as the beam exploded within him, rupturing his internal organs. The burning energy wracking his body, Spyler toppled face-first onto the pavement, erupting into a massive ball of fire.

Watching the flames burn, Gigan struck a victory pose, shrieking in triumph. He turned to face Wargilgar...

...Just in time to see the burnt, charred corpse of Megalon hit the ground.

Screeching angrily, Gigan took to the air and landed directly in front of Wargilgar. The cyborg slashed at the Terro-Beast, drawing blood. When he tried it again with his other arm, Wargilgar grabbed it before it could hit him. The two creatures grappled with each other for a moment before Wargilgar managed to knock Gigan to the ground. Gigan tried to get back up, but his Garogan foe was upon him in seconds, raining his claws down on him again and again. Gigan lifted his head and fired his cluster beam into Wargilgar's face, knocking him away. Gigan got back to his feet and flexed his arms. Shrieking angrily, the Terro-Beast leapt towards his foe, but Gigan managed to stay on his feet, shoving back. Wargilgar swung his arm up at the cyborg's face, snapping his pincers at his beak, but Gigan pulled his head back and dodged the attack. Gigan sliced upward with his left scythe, slicing off the strange, wing-like extremity from Wargilgar's corresponding shoulder. Gigan laughed as Wargilgar clutched at his shoulder, screaming in pain. The Terro-Beast soon recovered and opened his mandibles, spewing out another stream of searing flames.

Gigan shrieked as the fire assaulted his body. He tried to back away from the heat, but Wargilgar advanced, keeping the flames on him. Gigan cried out as he felt Wargilgar's fire burning him. He needed to finish this, and quickly. Two slits opened in Gigan's chest, and out shot twin, razor-sharp discs. They made their way towards Wargilgar, twirling through the air.

Wargilgar paid the discs little attention, which would soon prove to be a grave mistake.

They sliced through Wargilgar's long neck, immediately cutting off the flames. The Terro-Beast stood there for a moment, unmoving, before the upper half of his neck detached and fell to the ground with a thud. His body soon followed, crashing to the street.

For a moment, Gigan stared at the decapitated body of Wargilgar before rearing his head back and crying in victory. Though Megalon had fallen, Gigan had proven triumphant for his masters. Turning his attention back to the city, the Nebula M cyborg resumed his original mission: raining destruction down upon mankind.