It is bad enough that you steal anything that isn't nailed down and that you know how to open up childproof latches that the kids weren't able to figure out until I showed them at age 8. But the continual flushing of the toilet must.stop.NOW!
And I am not at all happy that not only have you learned how to flush the toilet, you also know how to open up the lid so that you can stand there and watch the water go down and refill.
You are missing a golden opportunity here! Teach him to sit on the toilet instead of the litter box, and since he already knows how to flush, you'll never have to change the litter box again!
He has a litter mate brother who, while quite sweet, is dumb as the proverbial box of rocks. I've actually never known a cat who runs into the wall, sits down and shakes his head and then slams into it again because he can't figure out that the wall isn't going to move for him.
Mike is extremely intelligent and an exceptionally annoying cat to live with. While he would be easy to train to use the toilet, he lives for his idiot brother using the box, because idiot brother has never learned how to cover up anything. Mike hangs around the box basically waiting impatiently for brother Spike to finish so that Mike (the groundskeeper is what my spouse calls him) can jump in and bury everything, smoothing it over so well that I can't always tell a cat has been in there.
Mike is the reason that all of the remotes are in a drawer. He figured out that if he (and lord, he is a patient cat), pushes buttons, eventually the tv will turn on. Scared the holy hell out of us several times at 2 a.m. when all of sudden the tv starts blasting some infomercial.
I have to put them in a drawer that doesn't have knobs as the little blankety blank has figured out how to hook his teeth around the knobs and pull open drawers with knobs.
He is always watching everything we do so that he can figure out how to do it himself. As stupid as it sounds, I shut him in the bedroom if I am going to be doing something that I don't want him to learn how to do by watching.