Creatures

"'Docking Station is the exciting multiplayer game from the creators of the Creatures series! This is no ordinary game. By playing with the Docking Station, you will be taking part in one of the largest-ever Artificial Life experiments. Not only will you be breeding your own unique artificial life forms, called Norns, but you will be able to connect your computer, through the internet, and form a part of a vast online world through which your Norns can wander at will. Best of all, it's completely free to download and play!"

http://www.gamewaredevelopment.co.uk/games.php?id=C0_37_10