It sounds like a good idea, but also very heavy on the programmer (workload and stress)
I think players would value the changing more if it were just a bored GM who logged on and started changing people in the square into creatures. Creates interesting role-playing situations.
I was a marse once. I will not say what I did.
But I did yell "BABABARARABNRBARBABRBARBBARLLLLLGH!!!" a lot.
