Jake is right. He's definitely in trouble and maybe he did this strategically knowing that Cougar couldn't hit him, but he really wants to shoot him with a beanie or something that will hurt him, but not damage him. Jake suddenly being intangible makes that impossible.

He gives him a sharp look that asks why he needs to keep touching and eating things that he shouldn't be, annoyed that he needs to be the sensible one, though not surprised. "Idiot," is all he says out loud, but Jake should know him well enough to get the rest of the gist.