Okay he has to just. Stiffen and look dumbfounded for a few moments because it's inconceivable to him that any one bot could ever be this annoying.

"Oh for the love of... I am Starscream!" he snaps finally. He's not even offended, because even he can see that this guy is just fucking with him for kicks now; he's just exasperated and wants this annoyance to cease.