When reading some work of a friend, I noticed the sentence "When in doubt ask me". Instead of simply pointing out that it could use a comma after doubt, I read the sentence aloud with no gaps or punctuation, as it is written. When I was corrected that there should be a pause, I smiled and remarked that there was no punctuation to indicate this and my friend realised their own mistake. When asked why I didn't just say that, I remarked that I was just being __ for the sake of amusement.
I used "spurious", but having re-read its definition, that is not the correct word to describe the way I acted, because it means:
Not being what it purports to be; false or fake: "spurious claims".
I don't think "sarcastic" covers what I did either and I'm at a loss for the word to use.