Starscream stands his ground, fully prepared to strike the first blow from the moment that Karkat gets back up in his face, but then the angry little creature continues with his empty threats and suddenly there's utter bafflement written all over his face. He blinks a few times in confusion. Transit canyon...???? Not that he claims to have an excellent understanding of human terminology himself, but he's fairly certain that none of that sentence was what anyone would strictly call "proper english".

Then he snaps out of that train of thought and, without any warning whatsoever, jabs Karkat right in the stomach with as much force as he can muster with the holoform; definitely not the effect he would like to get across were he using his real body, but should be enough to send a painful sensation of concussive force through the little vermins torso.