In the chamber engulfed by darkness, the robot encountered the murderer. Just as the human entered the polygonal arena, faint lights went on; crimson rays illuminating the floating dust.
"I'd like to warn you, child. You will not like what comes next." said the robot fiercely.
The human gripped his frying pan, and stepped forward.
As the robot made erratic and incomprehensible noises, bright and dazzling flashes of light burst out of its screen. The human stood still even when the parts of the robot rapidly rearranged and transformed him into his hostile form.
Mettaton NEO had risen.
The robot now had beautifully shining plasma wings, a sleek aerodynamic body, as well as lethal weaponry. However, unsurprised, the human simply sighed. Mettaton wondered: why wasn't the human fearful for his life? Perhaps the human noticed a flaw in him. The robot analyzed himself.
Suddenly, the human jumped at him. Mettaton only narrowly evaded his weapon, and the pan instead crashed into the floor. It was struck with such force that the pan penetrated the aluminium surface, and tore apart cables beneath. But the pan was caught inside, with the human attempting to free it.
Using the time available, Mettaton discovered a detail he had overlooked. The safety lock on his weapons was still on. After rectifying the problem, he faced the human - who was now preparing another attack.
Mettaton awaited for it, cautiously. When it came, he deftly dodged it. Still on the move, he turned his right arm towards the human. As a glowing orb of plasma formed at its end, Frisk's heart sunk. He looked around in panic. Frisk jumped to the side as Mettaton unleashed a devastating beam of fire. It lasted for only a few moments, but had left a glowing scar on the walls, and the stink of a fried motherboard. Frisk reluctantly swiped at Mettaton.
The robot, now confident in victory, flew out of the attack's trajectory, and then fired several rapid blasts, leaving little room for evasion. Despite Frisk's effort at dodging, he received severe lacerations. He screamed as he collapsed onto the floor. The agony was a fiery sensation like the sting of a thousand wasps. The scorched pan, which he couldn't bear holding, fell out of his trembling hands. It became apparent the child could not fight any longer.
Mettaton was delighted at the victory, but he felt a bit of guilt. Kneeling down by the human, he asked: "Did you learn your lesson?"
Frisk was gasping for air, and crying from pain. "Yes, I'm sorry," he said, his speech faltering. Pain overtook him, and his sight became muddy.
Seconds later, the agony disappeared. It was like magic. Frisk, surprised, turned to NEO. The robot, or rather, Mettaton, had healed him; had spared him. Frisk was intrigued.
"But why?" he asked. Mettaton sighed, with a hint of a smile.
"I thought that you could change as a person, my dear. Especially after feeling the pain you caused to others." Frisk thought about this deeply.
"Thank you," he said, with a genial smile. He picked up the burnt pan. Even though he had the chance to kill Mettaton, he simply followed Mettaton out of the arena. He was determined to change for the better.