BiomeChanger

BiomeChanger is a Minecraft 1.12.2 server plugin that lets operators instantly transform the biome of any area they're standing in with a simple command. Rather than changing just a single chunk, BiomeChanger flood-fills the entire surrounding biome region, seamlessly converting it to any biome of your choice — from lush jungles and scorching deserts to frozen tundras and mushroom islands.
Perfect for server admins who want to customize their world without regenerating terrain. Blocks stay exactly as they are, but weather, sky color, grass color, water color, fog, and mob spawning all update to match the new biome instantly.
Features:

/setbiome — change the biome you're standing in
/listbiomes — browse all available biomes grouped by category
/biomechanger help — in-game help menu
Flood-fills the entire biome region automatically
Permission-based access (biomechange.use, OP by default)
No dependencies, lightweight, plug and play

Created by emperorsmileyYT