What is Petz?
Petz (Dogz and Catz) is a series of games made by PF Magic dating back to 1995, in which the player can adopt their own virtual pets. Graphics technology is based on SNES game Ballz what means that animals are composed completely of balls, with a pseudo-3D look; althought the improvement is that the balls are attached to each other by lines.
In Petz everyone can play with cats or dogs, feed them and obviously breed them. There are some breeds in different colour variations to choose from and it is a lot of fun with mixing genetics. The community of players is creative and highly developed, and there are plenty of fanmade programs which allow people to do much more than game provides...
Making new breeed files - far different from original ones and more realistic - was a key revelation here. Because of this possibility of "hacking" file code and changing it to very different one, the circle of real cynology/felinology fanatics started to grow around this game. There is a lot of virtual organizations, virtual petz shows and other things of this sort (see my link page). Besides programs specialized in changing petz' physical appearance, there is plenty of programs which helps to take care over petz, control their weight, age, plan and make litters etc. There is also special tool to create items, and function of making whole new backgrounds and skins was build in a Petz since very start, so today almost every part of game can be customized and indeed, IS customized in almost every player computer.
To start, you can download Petz here.