Stalker

In the heart of a sprawling galaxy, where stars blazed brightly, lived a tiny creature named Xylia. Unlike her fellow parasites, who were microscopic and harmless, Xylia possessed a sinister secret - she was parasitic. Her tiny body, no bigger than the head of a pin, bore the scars of countless invasions and took over the regulatory systems of her host organism, a humble planet named Zephyra.

Xylia's parasitic nature allowed her to manipulate the planet's environment in ways she never thought possible. She controlled the weather patterns, manipulated the temperature, and even changed the color of the plants and animals. But Xylia's powers were not without limits. Her energy consumption was immense, and she needed constant sustenance from the planet's resources.

One fateful day, a rogue spaceship, seeking to explore the uncharted territories of the galaxy, landed on Zephyra. The spaceship's crew, led by the ruthless captain, Admiral Zarthus, set their sights on Xylia and her parasitic ways. They desired to harness her power for their own sinister purposes, believing that she could be used to create a weapon of destruction.

A fierce battle ensued, where Xylia's small size gave her an advantage over the spaceship's advanced weaponry. She skillfully dodged lasers, manipulated the planet's climate, and released a torrent of deadly spores that infected the ship's crew. Although the spaceship's defenses were formidable, Xylia's tenacity and adaptability proved too much.

With her victory, Xylia emerged from Zephyra, a legend whispered among the parasites. She had saved the planet from the brink of destruction and become a symbol of hope and resilience. And so, Xylia, the parasitic alien who took over Zephyra, continued to protect and guide the planet's ecosystem, proving that even the smallest creatures can make an immeasurable difference in the grand tapestry of the universe.


Additional Context:
(Stalker),
"a parasitic alien on a microscopic scale invades its host and take over its regulatory systems... and then goes nuts"