The guys had blown them up earlier for some sort of celebration for Kudelia, who'd turned 17 a few hours ago. Mikazuki couldn't fathom for the life of him why people wanted these things, that Kudelia had called "balloons", near them.
He'd seen them fly around a lot and go everywhere, and they made funny sounds when one of the guys, usually Ride, forgot to tie them up. He might've liked them.
But then Shino jumped on one and made it go bang, and that had sent him into cover, thinking they were being attacked.
Now Mikazuki doesn't like balloons.
...
Prompt: Balloons