Ok ok!
So... Caves of Qud.
That game seems very much like a MUD to me... what I think of as the general style and kind of gameplay... but it is not MultiUser, its a bit fancier than totally text based... but it does very much do a whole lot of basically 'deep world simulation'.
I did actually play a tiny bit of Everquest, waaaay back in the day, maybe thats where I'm remembering the 'graphical MUD' term from?
Christ, was that before RuneScape even existed?
Oi, lol.