Biome changer block/command

So basically it would be a way to change a biome you preferably would only get it in creative and through a command. If it was a block it would work  similarly To the light block when you place it you can’t interact to with in survival but it wouldn’t be possible to change it back to its previous biome without the block and it would allow the ability of the fill command. If it was just a command to change a big area it would be easier than placing each block individually but it would be a more choppy transition form another biome. This command/block would very helpful for map creators that are using a flat world for there map so they could get mobs form that biome to spawn naturally and to have the grass and leaves and weather match the biome they want and to make it simpler it would be the core biomes that are possible to change it to so for example you wouldn’t have the option of snowy tiga and snowy tiga hills because really the only difference would be the generation between the two and you wouldn’t be generating the area you are changing to a different biome.