Mint being dumbstruck means Mario is similarly dumbstruck for a moment, like a little there's a little loading symbol floating over his head as the connection struggles to go through. But when Mint says yeah, sure, she's a cat, that's the end of the question for Mario. Maybe he was expecting a correction, a more detailed explanation, or something, but okay! It's not a big deal for her! So it's not one for him, either!

"Cool!" he says. He has still, objectively, seen weirder.

"I'm Mario, by the way! What's your name?"