Necropolis Dungeon

An underground Dungeon made to look like a catacomb/necropolis. it would be filled with rooms that have loot and undead enemies, connected by long hallways decorated with coffins/caskets/skull banners/ ect

There would be a boss in the Center of the dungeon: The necromancer. he would be an illager of some sort, and would summon undead mobs to attack you. once you killed him, you could get a totem of undying, an undead mount, emeralds, or some sort of magic staff.

This would add to the currently lackluster ammount of dungeon crawling options and explain where the undead come from.