The premise of this joke is nothing particularly original. It's simple, entirely predictable misdirection. Jim Meddick seems to recognize this and doesn't even really try to hide it. It's not hard to envision the strip ending on the third panel, in which case the misdirection would have been the whole joke, and I probably would have made fun of it for being lame.
But it doesn't end on the third panel. Instead, it ends with a terrifically funny punchline in the fourth panel. And so, in a fairly rare turn, I've posted about this comic not because it's terrible, but because it made me laugh out loud.