What do you dislike about it? I know its not the best, and would love critical feedback on how it could be better.
It immediately displays a bar at the top of the altered page making it too obvious
I was going for obvious. There is (currently) a way around that. I say currently because I have updates to fix it.
I know this would be a "fun tool" for some people to play jokes and pranks on other people, but cannot in good conscious let that happen without /some/ level of indication.