On planet SR388
The chozo scientist surveyed the room, seeing that all was going well. The other scientists had left but he was staying late to check up on things. He walked over to a glass cylinder with a creature hovering inside it. The creature reacted to the shadow cast by his tall figure and rammed the side of the container, screeching. The creature was hungry. The scientist smiled at the creature and observed that it was healthy and was growing nicely. The creature resembled a transparent globe with organs visible inside of it and two curved mandibles protruding from the bottom. The creature was codenamed "metroid", which meant "ultimate warrior". Him and the other scientists had spent five years engineering the creature and they were finally almost finished. He was so proud. This creature would solve all of his planets problems. It would provide cheap, reliable energy to the people and vanquish their enemies. He couldn't be more wrong.
The Motherbrain patiently waited and plotted in cavern in the deepest recesses of Zebes. This Motherbrain was, as it's name suggests, a giant brain. It had recently been awakened from its 3,000 year slumber by an earthquake. It fed, and grew stronger from the psychic brainwaves from the denizens of the surface. The chozo had sealed it under the earth so long ago to stop its diabolical plans. The Motherbrain would have its revenge for their insolence. It reached out with its psychic waves, influencing the minds of the galaxy. It spread corruption and fear among the many peoples. Thanks to its influence the metroids were being developed and many were joining the ranks of its favorite pawns, the space pirates. All was going according to plan. It would just have to wait a few more years, but it did not mind. A few years are as nothing to a being who had been perfecting its scheme for the past eternity.
Maroko and several other Chozo were in a craft headed for Zebes. They had just escaped their planet, SR388. The entire planet had been overrun by these strange, new "metroid" creatures which were created by some scientists. It had been so horrible. Over a hundred metroids escaped from a government laboratory and started latching onto everyone and turning them into ash. The chozo had never encountered anything like this before. Most of their weapons were entirely ineffective. Lasers bounced off of them. Explosions just made them angry. Bullets barely broke their skin. In less than a single day their entire civilization had been destroyed and the survivors had no choice but to flee.
Maroko was joyous to see Zebes on the viewscreen. Surely, they would be taken in there. He looked over at Owlof who was deep in thought. Something wasn't right though. He felt a strange presence and could hear a low humming noise. A metroid flew right over his head and latched onto Owlof's face! Owlof let out a horrific scream as he dug his claws into the metroid, desperate to remove it. Maroko shocked the creature with a stun gun but the electricity had no effect on it. In fact, the electicity seemed to make the metroid happy. The other chozo on the ship were running about trying to find anything that could stop the metroid. There was nothing they could do. The metroid let go of Owlof's face. All that was left of him was ash and dust still in the shape of his body. The metroid rammed into him and he crumbled entirely.
Maroko ran into another room and locked the door. One of the other chozo pounded on the door.
"Please, for ancestor's sake, don't leave me out here!" Maroko didn't answer. He was too afraid to open the door. The metroid might fly in. He fell against the wall and tried to block out the sound of the other chozo dying just outside the door. He was so ashamed of himself, but what could he possibly do against such a creature? It was better that he survive than no one survive. He sat against the door, his eyes closed, trying not to think. It had to all be a nightmare. Things like this surely couldn't be in a sane universe. Startled, he opened his eyes. He heard clanking noises and they were getting louder. He pressed his ear against a wall, listening for the noise.
"Yes!", he thought to himself, "A rescue team, someone has noticed our distress and is boarding the ship to save me!" Maroko then heard something metallic hit the floor next to him and looked over. Unfortunate for him, he had been wrong. There was no rescue team. The metroid had gone through the ventilation shaft and had just broken through into this room. He shrieked in terror and ran into a corner. He swung his fists madly as the metroid neared him and missed.
The hungry beast clamped it's jaws around his head and proceeded to drain his very life force. He had never felt such pain before. It felt like someone was jabbing him with a thousand needles while tearing his head off. He clawed frantically at the creature, but to no avail. He felt himself weakening and everything was soon dark. His arms went limp and dropped. The metroid, now full and satisfied settled down on a desk to take a nap. Before it could fall asleep however, the ship crashed into the surface of Zebes and was instantly destroyed, the debris scattered over several miles.