Petz 4 is a game developed by PF Magic in 1999 for PC. The two species incuded are cats and dogs, stylized as catz and dogz, and each pet has a unique code and genetic makeup. After a few generations their genes can mutate, resulting in coat colors that don't occur without high generational breeding. These petz can be fed, groomed, dressed, played with, have unique relationships with others, and cannot die. The only way a pet can "die" is if their file gets corrupted.