Amazing, isn’t it? Mark asks what a Bassigator is, while forming the exact same image in his head that Rusty did, yesterday. Is he deliberately playing Rusty?
And could Mark act any more condescending? In panel 2 Rusty declares he wants to prove the Bassigator is real, only to have Mark in panel 3 first claim he understands (“I see.”), then ask if Rusty wants to prove whether the Bassigator is real. Duh! Perhaps Rivera just made a mistake, since she could have left out Mark’s second sentence and stuck with the first and third statements in panel 3. Leaving it in fortifies the impression that Mark is patronizing Rusty.