Get out of my business!!!

Many people at my work hate their jobs so much, they get pissed when they find out I like my mine. I had a person that has nothing to do with my job, he is not my supervisor, and he runs a completely different part of the company telling me I should put in 8 hours one day. I turned to him and asked "did you become my supervisor last night." He said no but I have been tracking your hours and you haven't put in an 8 hour day in weeks. Mostly just 5 and 6 hour days. The great thing is he didn't know that he only sees 1 to 2 thirds of my job depending on the day. I told him to take it to my supervisor and I don't have to answer to him. I gave my supervisor the heads up and he said he would question the good use of that supervisors time, track other departments instead of taking care of his own department. I like having the right people on my side, and I'm pretty good about covering my back side.