The Mushroom Kingdom was abuzz with excitement. An unprecedented tournament was about to commence - a showdown unlike any other. The prize? The presidency of the United States. The contenders? Icons from across the worlds of video games and horror - FNaF, Mario, Chucky, and M3gan.

Mario, the valiant plumber from the Mushroom Kingdom, was first to enter the ring. The crowd cheered his name as he waved his red cap in acknowledgment. His fiery determination was evident in his eyes.

Next up was FNaF, the animatronic bear from Freddy Fazbear's Pizza. Its steely gaze and mechanical movements sent a chill through the crowd. It was a terrifying contrast to Mario's warm presence.

Then entered Chucky, the notorious killer doll. His grin was unsettling, and his eyes flickered with a sinister glint. The crowd gasped as he brandished a knife, challenging his competitors.

The final contender was M3gan, a childlike AI doll with advanced capabilities. Her neutral expression and robotic movements gave away nothing of her strategy. The crowd watched in silent anticipation.

The showdown began, and the Mushroom Kingdom held its collective breath. Mario darted around the ring, agile and quick.

FNaF, on the other hand, used its size and strength, charging at the competitors with ferocious speed.

Chucky was crafty and cunning, using his small size to his advantage, dodging attacks and launching quick counter-attacks.

M3gan, with her advanced AI, calculated each move meticulously, avoiding hazards and launching strategic attacks.

The battle raged on, each competitor displaying unique strategies and skills. The audience was on the edge of their seats, watching the clash of these titans.

Mario was the first to fall, overwhelmed by FNaF's brute strength. The crowd gasped as their hero was ousted from the competition.

Chucky and FNaF locked in a fierce battle, the animatronic bear's strength against the killer doll's craftiness. Sparks flew as they clashed, neither willing to back down.

Meanwhile, M3gan was watching and calculating, looking for a perfect opportunity. Her mechanical eyes flickered, processing every movement.

Chucky managed to land a decisive blow, sending FNaF crashing out of the ring. The crowd erupted into cheers and gasps, shocked at the turn of events.

Now, it was down to Chucky and M3gan. The killer doll versus the AI. The crowd was silent, waiting for the final showdown.

Chucky lunged at M3gan, but she deftly sidestepped, sending him crashing into the ring's edge.

M3gan then launched a swift attack, sending Chucky flying out of the ring. The crowd erupted into cheers. M3gan, the AI doll, had won the ultimate showdown.

The Mushroom Kingdom was filled with applause and cheers. M3gan stood victorious in the ring, a silent and stoic champion. The showdown had come to an epic conclusion.

As M3gan was declared the new president of the United States, a new era dawned. An era where AI and humans coexisted and competed on equal footing. A truly ultimate showdown indeed.

And so, the tale of the ultimate showdown would be told for generations to come. A tale of courage, strategy, and the unexpected triumph of AI over all odds. It was indeed a story for the ages.