(Picture Harry thinking Snape's a hologram and poking him. XD Then think of Snape's reaction. Snape: -stares- Don't poke me.)

Harry blinks at Snape. "No, I didn't. I thought you were in there. Which you're obviously not, unless you're a hologram." He looks slightly amused at that. He watches Snape's reaction to his comment, knowing he's going to pay for being 'insubordinate'. He doesn't seem to be afraid of that though.