Welcome to Virtual Pet Yoshi!
In this game, you get to care for your own pet Yoshi! Your Yosh will start out in an egg. You must give it grass to help it hatch. When it does, it will be one of eight possible colors: Green, Red, Blue, Yellow, Pink, Light Blue, Orange, and Purple. You can feed your Yoshi, let it play, or have it take a nap. If you stay long enough, it'll grow into an adult! Be careful, though, because your Yoshi can run away or even die.
Credit to Cheeseman for the Goonie (Bird) sprites.