Accept

You agree to Blue's challenge. "Alright! Time for you to loose!"

The battle begins with Blue unleashing his squirtle from his pokeball. You respond by taking out Charmy.

"Okay, Squirtle, ram this doofus with your shell and bring a quick end to this fight!" Squirtle then jumps towards Charmy and then retreats into his shell with an intent to slam his body into him.