After school was out for the day, Umaru Doma proceeded to head on back home to return to her Indoor Mode time. But she was stopped by a blue-haired girl with flower petals in her blue eyes that happen to go by the name, Sylphynford Tachibana. She wanted to prove to Umaru that she is the best and the most intelligent girl in school.
"Umaru-san, I challenge you to a battle to see who can be the biggest and the cutest blimp!" Sylphynford demanded while pointing her finger with her kitty cat like mouth.
Umaru thought about the offer for a bit but accepted the challenge anyways. She wasn't going to hesitate to not turn down the challenge because after all, she's very intelligent herself as well.
"Challenge accepted, Sylphynford," Umaru smiled in determination. "But I won't go down that easily!"
The two girls headed out of the building together so they can find a huge open space to begin their duel.
"I will not lose to you, Umaru!" Sylphynford declared with confidence. "I'll be the cutest and the biggest balloon in this school and everyone will love me!"
"We'll see about that," Umaru replied. "Watch out for UMR!"
Umaru and Sylphynford both took out their own pieces of candy and threw them into their mouths. They started to chew on them at the same time while Sylphynford sneered a devious glare at Umaru.
"I shall be the number one player! I am TSF!" cried Sylphynford.
As soon as both Umaru and Sylphynford swallowed their pieces of candy, they suddenly began to inflate like balloons. Their bellies were the first to expand following up with their entire bodies filling up with air.
"Let the inflation commence!" cried Umaru while watching herself expand larger.
"Desuwa! I bet I can inflate faster than you, Umaru-san!" Sylphynford taunted excitedly.
Both the girls continued to expand larger as they became bigger and rounder than before. Their breasts also started to inflate while their arms and their feet sunk deep into their ballooned bodies including their heads sinking like a quicksand. By the time they were done inflating into the size of 10 ft. diameter blimps.
Both the girl's school clothing stretched out the more bigly they got as well as their panties showing. Sylphynford's poofy skirt became wider as well as Umaru's red skirt including their shirts showing no signs of tearing.
"Let's see if I can win this one, Umaru-san," Sylphynford said as she bumped Umaru's ballooned body. "I'm just big enough to be the biggest and the cutest blimp in the whole entire campus."
"Not by a margin," Umaru shot back realizing that she's even bigger than Sylphynford and returned the favor by bumping her rival's ballooned body. "Looks like UMR is the victor once again!"
Before Sylphynford could reply, she realized that people are watching her show off, including her brother watching who had unknowingly joined the audience to watch her sister have a blimp battle against Umaru.
"Big brother is watching me," Sylphynford said feeling embarrassed. "But this will not be over yet, Umaru-san!"
Umaru and Sylphynford had quite a fun blimp battle but Sylphynford is persistent on defeating Umaru Doma one day. But only time will tell if a certain event will happen depends on Umaru being the unbeatable girl in her classroom.