New mobs for Ice and Desert

I think they could add new mobs that could help the game. There are not a lot of desert mobs or ice mobs. They could make something like ice piranhas, they travel in schools, swims under ice and can break regular ice and packed ice to attack the player, they could drop scales that you can use to craft potions. For the desert, there could be a snake that blends into the sand, makes a rattle noise before striking, and drops stuff for fire protection potions. There could be new structures that hold loot and bosses like a pyramid that contains a dugeon and the Necromancer boss from Minecraft Dungeons that summons skeletons with spears, shoots a small beam, and tricks the player by making illusions of itself. In ice biomes there could be a frozen watchtower that has the Iceologer from Minecraft dungeons and the mob vote. It summons ice over the player and rarely drops an ice wand