So basically a world where the pets go crazy and your pet go's crazy too. example if your pet has a may cast fairy it will until you beat the world have the opposite affect so instead of 400 you will take 400 damage and instead of plus 5 defence you will get 5 less defence so players will until equip their pets making the world a challenge considering some wizards only win because of their pets helping them this would be a fun sideworld for champions. And if you beat the final boss with a pet equipped you will lose the pet but receive the same pet as an egg with plus ten pedigree and a legendary non breed able pet for your class ( these can only happen once on a character. And the enemys of the world will all be pets so fighting a storm core as a general enemy. And the final bosses should be determined by the classes of the wizards in the battle so if you have a fire storm ice and myth wizard you will have the same class enemys. The final bosses should be immune to their class and the opposite class. Last thing about the final bosses they will be the legendary pet for your class you get and I have no clue about why they would go crazy maybe other wizards could come up with a reason why and the world should have to be accessed by a portal in pet pavillion.
I love the idea, for me I find most of game content pathetic easy, this would pose a good challenge and I think many hardcore players will agree with you. I would do it personally just for kicks, and use lower armour for the excitement levels.