Linear Tomb/Dungeon

A straightforward mini-dungeon with six separate encounter rooms/spaces. Easily slotted into any campaign that deals with any amount of dungeon-delving.

The suggested structure is as follows, from entrance to end;

Small Room; Spike traps in floor.
Large Pillar Hall; for introductory combat encounter.
Bridge and Balconies; For crossing under enemy fire. (Undead archers or the like)
Loot Rooms; Armory and altar.
Puzzle Encounter; Retrieving the correct object from each coffin (in the sides of the room) and placing it on their respective monument while under attack by never-ending undead assailants. Once completed, the final gate opens.
Final Encounter; Necromancer, Lich, or whichever flavor of monster suits you best.

The rooms are fairly barren, however, to make sure there's plenty of space to add whatever fits your campaign the best. Unfortunately, the entrance (staircase) wouldn't fit within the slab, but can easily be replicated with a simple staircase or other means of entry.

Some details lifted from TheConsummateNerd's Dungeon Catacombs Slab Pack.