"It's not fair in the only one growing up and exposing his privates", complained Carlos. "What do you mean?" replied Mr. Mendes. "That you should replicate the spell on someone else." Carlos grinned while he looked around at his classmates who seemed way more smaller now that he's an adult. The boys glanced at each other with terrified looks in their faces.
"Who wants to be a grown up like Carlos?" Mr. Mendes asked. "And being nude in front of everyone? No thanks." Jason replied, he was very well known as natural leader by his classmates. He was tall, blond and very athletic, so everyone includes Mr. Mendes consider him as one of the most handsome boys at school. "Oh, it seems cute boy needs a change of mind." Carlos said and mr. Mendes played along with him.
"No, no, no. Please! I don't!" Jason replied but Mr. Mendes has already casted his spell on the boy. To prevent he could ran away, Carlos took advantage of his new size and strength to Hugh him and start to undress him. Despite of Jason's protests his clothes were taken off until he was wearing only a jockstrap. Jason was tall, but even though he stood about a foot shorter than Carlos. His body showed no development, no yet at least.
The changes were subtle at first. No one noticed anything except for Carlos who noticed that Jason was a bit taller than before. Carlos smiled, he knew it was just a matter of time before he can't keep immobilizing him. Soon, Jason's body started puberty. He felt a tingle in his crotch. An strong itching was growing into his jockstrap but he tried to stay calm until someone exclaimed, "Look! He's growing hair down there! It's so much that it's poking out of his clothing" Jason's face reddened in shame as he ignored that hair also began to grow around his ankles. His hands and feet had already grown out of proportion. The remaining baby fat on Jason had melted away. There was only a lean body left.
Mr. Mendes noticed that Jason was already as tall as him. He was now only half a foot shorter than the Carlos and still growing. Jason looked around the age of 14. Then, the class watched in awe as Jason experienced a growth spurt. His jockstrap was now very tight on him and failed to hide his growing penis, which was experiencing its own growth spurt. His limbs continued to stretch. Hair started to sprout everywhere; his leg hair thicken while softer hairs appeared on his arms. "You're becoming pretty hairy!" Carlos shouted excitedly. "Let's everyone see what are you hiding under your arms!!" He lifted Jason's arms and the class could see two thick tuffs of underarm hair growing underneath. Peach fuzz appeared on his face and was still growing thicker.
Jason continued to grow, meeting and soon surpassing Carlos' height. Suddenly, a ripping noise was heard as his jockstrap could no longer take the growth. "Oh no! Please everything but that!!" Jason cried out in a deeper voice as his privates were exposed. A rush of adrenaline got him free from Carlos and he immediately tried to cover his genitals but it was too late. Everyone got to see the forest of blonde pubic hair that had developed. His dick and balls were also bigger, his dick was about 5 or 6 inches long, his balls had grown a lot in size and they're covered in hair too. Jason was now about 18.
The growth in height had slowed down, but his muscles started developing at an alarming rate. He was becoming very buff like a pro football player in a matter of minutes. His leg muscles pushed out, his biceps enlarging. His chest heaved out, and his stomach formed a solid eight-pack. "Wow! You're really big!" Carlos exclaimed. "I'm too big!!" Jason replied ashamed. His voice had deepened to a very manly tone. Jason's height growth stopped, putting him at almost seven feet tall, practically a foot taller than Carlos.
Then, the only remaining changes were on his body hair which continued to thicken all over him. His leg hair could now be seen from the back of the classroom. His arms took a similar appearance. His pubic hair peaked, forming a thick trail in the middle of his torso, meeting the pelt of chest hair that grew all over his pecs. Jason felt more itchiness on his face as its peach fuzz was replaced by a short beard, covering his jawline while it's squaring off. The growth in his crotch slowed down, his penis was around eight inches, his balls the size of lemons. The changes stopped.
"What a rush!" Jason said as he seems dizzy for some reason. In the middle of the classroom, now there stood two naked adults... and Mr. Mendes.