New Structure for Rare Biomes

What if there was a new structure for certain rare biomes? I.e., jagged peaks, snowy slopes, etc. Possibly a rare tower (not like a pillager outpost, but made of stone brick instead. It could have vines and moss on the sides. It could be in about 5% of these rare biomes and contain loot similar to that found in fortresses.

Mobs: The tower could spawn illagers around it, with an illusioner boss at the top floor. It could be a good way to incorporate it into the game. It could have allays too, and have a rare basement with a mob spawner, similar to a that of an igloo.