As you may know, Cat Petterz 2 is one of this admin's favorite games. To those that don't know, it's a game where you take care of a cat and raise it. Sounds simple, right? XD
Actually, the game has a REALLY deep animation and breeding system... So players have been able to hex edit the game data to create brand-new pets.
If you download the right mods, you can raise birds, hamsters, cars, cartoon characters, and even more. Mewmewqueen's Sympton family pack is a great example of how far things can go.
However, you have to be careful, because, not all mods are very compatible. When pets fall in love, an egg appears and it hatches into a new pet that combines the animation and visual data of the two parents. Meaning, if you try to breed a hamster and a car, you'll either get a complete freak of nature XD Or, worse, you'll get this message.
"Incompatible pet"
Then the game will freeze and the music will glitch out.
I was so scared of seeing this message as a kid, I would punish my pets so that they would NEVER fall in love. If an egg did appear, I would throw in the trash right away.