"Reversen" dimension

A new dimension named the “Reversen” where it is quite like both over world and the nether at the same time. It would have new biomes such as Fantasia which is a bright and colorful and has waterfall that might have some secret loot in it and there will also be some scarier biomes to bring the sort of magical theme into it such as the ScarnLands where phantoms can spawn any time randomly and there can also be odd ones such as the retro biome where verything is black and white. There would also be different mutations of the mob depending on which biome they spawn in. A zombie could be really big and scary in ScarnLands and do more damage but could do less damage in Fantasia and be a pretty color. a new boss if possible. in order to spawn him you have to collect one item from each biome and the boss would drop a new weapon called the advanced bow which does twice as much damage as the regular bow and unbreakable would also drop 2 special matching banners as tokens