Harry decided to use the new shipment of speedos as a preteen exclusive when a boy of ten walked in.
"Hey Zane, check this out." Harry said holding a red speedo.
"That's a nice speedo, what's it do Harry?" Zane asked.
"Gives you a superhero build, unlike regular speedos." Harry answered. "Though there's a catch."
"What catch?" Zane wonders
"You must be nude before putting it on." Harry replied. "You'll also get a surprise as well."
"Then all i have to do is remove my briefs." Zane comments as he steps out of them.
"Then here you go." Harry said handing the speedo to Zane who slowly began sliding it up his legs which were gaing muscle.
"Cool, my legs are stronger!" Zane exclaimed when he saw them as he held the speedo at his knees momentarily before moving it up to his hips which caused all the fat in his body to go right to his butt making it super bubbly and moaning as he gave it a slap without realizing it. "Wow, almost done changing! My butt is so round, it's easily my best feature."
"That's for sure." Harry said as Zane pulled the speedo all the way to his waist completing his changes with an eight pack, tan and blonde highlights in his pale blue hair alongside other impulses. "Also i'm sure you figured out the other part?"
"Yep, find others to change into super speedo dudes." Zane spoke as he touched his rear again and released into his speedo. "Oh that feels so good!"