In the colorful world of Toy Story, where toys come to life when humans aren't around, lived Rex, a timid plastic dinosaur. Rex was afraid of his own shadow and rarely roared, making him the butt of jokes among his friends.

One sunny day, Rex decided he'd had enough. He decided to prank his friends – Prospector, Slinky dog, Bullseye the horse, and Jessie the cowgirl - with a mighty roar to give them a taste of their own medicine.

However, Rex was still struggling to overcome his timid nature. So, he decided to seek help from his other toy friends. Together, they hatched a plan to help Rex reveal his mighty roar.

His friend Hamm the piggy bank suggested, “Rex, you need to face your fears. Try practicing your roar in front of the mirror!”

Encouraged, Rex tried to roar in front of the mirror. He saw his reflection shaking in fear, and it made him laugh. This was the first step toward overcoming his fear.

Next, Bo Peep, a porcelain shepherdess, cheered him on, “Rex, believe in yourself. Your roar is within you, waiting to come out!”

Taking her advice, Rex started to believe in himself. He tried to roar again, and this time, it was less of a squeak and more of a roar.

The next day, Rex put the final phase of his plan into action. He was ready to prank his friends with his mighty roar.

Prospector was napping near a pile of toy gold nuggets. Rex snuck up behind him and let out a roar. Prospector jumped up, startled and looked around in surprise.

Buzz Lightyear, a spaceman toy, who had been watching the prank, laughed, “Well done, Rex! That was a mighty roar!”

Next, Rex found Slinky lazily stretching near the bookshelf. Sneaking up, Rex roared, causing Slinky to spring up in the air in surprise.

Woody, a cowboy toy, clapped his hands in glee, "Rex, you're becoming quite the prankster!”

Bullseye was munching on play apples under the table. Rex approached him quietly, and with a mighty roar, he startled Bullseye, who galloped around in surprise.

Jessie was the last one. She was practicing her lasso skills on a toy cactus. Seeing Rex approach, she got ready for his prank.

Rex roared as loud as he could, but Jessie, ready for it, simply chuckled, “Good one, Rex. You sure got us good!”

From that day on, Rex was no longer the timid dinosaur. He had found his voice and the ability to stand up to his friends.

His friends loved this new, confident Rex. They were excited at the possibility of more friendly pranks and adventures with him.

And so, Rex, once timid and shy, became the life of the toy parties. His mighty roar was now a source of joy and laughter among his friends.

Rex was proud of his transformation. He realized that he could overcome his fears if he believed in himself and faced them head-on.

His friends were proud of him too. Even though they got pranked, they loved the new confident Rex. After all, it was all in good fun.

And so, Rex's pranks became a beloved new tradition among the toys. Every day brought new opportunities for fun and laughter, and Rex was at the center of it all.

All the toys realized that surprises and changes could be fun. They learned to embrace Rex's new antics, and it brought them closer as a family.

As for Rex, he was enjoying his new-found confidence. He looked forward to each day, eager to share laughter and joy with his friends.

And that's the story of how Rex, the timid dinosaur, found his mighty roar, not to scare, but to bring joy and laughter to his beloved friends.

Life in the Toy Story world was full of adventure, fun, and laughter, and Rex, with his mighty roar, added a new twist to their amazing world.