Tamagotchi

Tamagotchi is a game based on the popular virtual pet of the same name. In it, you select an egg from the laboratory, and then it hatches in its room. From there, you are fully responsible for its care. Everything from feeding, medicine, playing with it, cleaning up its poo and scolding or praising it when appropriate - you must do it all. Unlike the actual Tamagotchi toy, the Game Boy version is not in realtime. (mobygames)