This is a story I created for my 5 year old niece.

During the old times, things were not as they are now.  Dangerous monsters lurked around every corner doing the ***** deeds of the gods. The innocents had no protection. Only their own wits could keep them living another day.
Such was so for Elephant, he was one of the most intelligent of all the animals in the forest. He was large and grey, wizened with age. He had dark eyes, full of knowing. He had a strong face, with a large round nose. He was the guard of the forest, a scholar, and he could even read, unlike so many of his predecessors. He protected the innocent animals from the evil ones who meant them harm. The gods envied his intellect. They were afraid that it surpassed their own.  They wanted the innocents to be consumed by their minions, the dangerous monsters that lurked around the outside of the protection circle.
They devised a plan to destroy Elephant once and for all. They got their scariest, meanest, largest, most determined beast to do their bidding. The Mushika, some called him “The Mouse”. The Mushika had never been seen before, he had only been a whiff of a rumor found in children’s stories. He was said to be as large as the biggest trees, as mean as all of the god’s combined, and as powerful as the forest itself.
The god’s were able to convince the Mushika to do their bidding, by promising to make him even larger, meaner, and more powerful than he already was. He agreed and began his journey towards the innocents’ home where Elephant stood ready to protect and defend.
Elephant could feel it in the wind that something was coming. He read the leaves on the water to be sure. He knew that danger was almost on them and prepared for battle. He stood quietly, his eyes slowly moving from trunk to trunk. The wind blew slightly, ruffling his long ears. Then, THUMP. THUMP. THUMP. It seemed as if the whole forest quaked. Far away, trees began to fall to the left and to the right. Slowly, it got closer and closer. Until the Elephant could see a looming white beast with red eyes, a pink nose, round ears, a long pink tail, and a massive body.
He roared, “Elephant, I have a bone to pick with you!!” Elephant’s face was calm as he stepped forward. The Mouse lunged stepping on the Elephant’s trunk. Elephant howled in pain, jerking and tossing away from the Mushika’s massive foot. The Mushika persisted, realizing that he had made Elephant utterly defenseless. He opened his giant mouth, full of sharp teeth, about to swallow Elephant whole.
Elephant’s eyes filled with fear, then sharp determination. He mustered all of his strength together and made one final, gigantic tug. His round nose stretched and stretched and stretched, then popped out from underneath the mouse’s foot. He realized he was free, and wasn’t focused on how his nose had become elongated. He shoved with all of his might against the Mushika who was very startled sending him back against the trees. The Mushika had been knocked out.
Elephant called out to the innocents, “Family! We must flee now before this mouse wakes up. We must go where not even the God’s can find us!” All of the innocents came out of their huts.
One of the children, Giraffe, asked, “What happened to your nose?”
Elephant replied, “It has been stretched out, but do not worry. I am fine. We must go now!”
So all of the animals packed their things and went to a hiding place. Elephant realized he could grip things with his new nose. He picked up a giant rock and began to crack the ground away from the rest of the forest. It broke off and floated away, millions of galaxies away. They decided to call this place Earth. So that was how Earth became.
Later on, when the Mushika woke up, the gods were waiting for him. “You have failed your mission, therefore you must be punished,” they said in unison. The mouse quivered as they began chanting strange words. Slowly his size diminished to the size of an apple. He squeaked, no longer able to roar. The god’s laughed, snapping their fingers. The Mushika was suddenly on Earth, where his dreadful enemy was. The Mushika had been stripped of his mighty name and put into unfamiliar territory with no allies. Forever to be called Mouse, never to be able to defend himself again.
Elephant knew that Mouse had been punished for loosing their battle, yet he was still terrified that he would change back into that horrible beast. He feared Mouse the rest of his life, and told all of his family to fear him as well. This story explains why the elephant’s trunk is so long, why mice are so small, and why such a large animal as the elephant is scared of such a small animal as the mouse.