Thinking about a tombs of monarchs, and others of wealth and power, that have the ugly tendency to get looted, I came up with this:
A relatively cheap “trap” could be a simple corpse. Not just any corpse, mind you, but one that has died from some highly infective disease. Simply include the body (bodies) in an entry hallway, or some easy to access room where thieves are likely to enter/break in. Optionally equip it with some treasure, to make them search it and contract the disease.
Don’t forget the death curse, it looks much better!
While infected corpses in their very own grave may conflict a bit with afterlife or personal preferences, they should mostly work:
- germs can stay active for a long time (though people may not know about it)
- diseases that were overcome (or survived…) centuries or millenia ago may be still dangerous to the people. Even if the hardy adventurers survive, or simply cast that Cure Disease spell (sic!), they may carry the “Black Pest” with them… talk of a major campaign modifier. And don’t forget to pursue madly the culprits that unleashed the curse of Rhudolf the Vengeful…
- maybe all that live now are descendants of those that survived the pest, and are immune. Just think of the minor flu one character develops, and it turns lethal for a people/race that arrived after the plague was overcome!