Traps in dungeons and tombs can be a bit hackneyed, but it’s just one of those things that people expect. Did these things really exist? Sure, but the traps in the real world can take forms we never thought of when it comes to our games.
Haematite powder was spread around in some tombs and chambers. This fine powder is jagged at a very small level and can be intensely irritating to the skin. If inhaled it can do permanent damage to someone’s lungs in much the same way as asbestos or coal dust. Not immediately deadly, but pretty vindictive.
Cinnabar is a bright scarlet form of mercury-sulphide, the mercury (absorbed in fumes or from the dye) causing itching, impaired senses, swelling, peeling skin, discolouration, sweating, heart problems, high blood pressure and death. Ritualistic burials sometimes coloured the bodies and their grave goods with cinnabar.
A popular trap in many tombs, though the water might evaporate or run away from its holding tanks if far from replenishment sources. Typically a false wall or carefully balanced support will give way, allowing the water to flood out. In cold climates it may be salt water, to prevent freezing and to it any thieves with much colder water.
Some real world ancient tombs have had sand hidden in much the same way as flooding traps above. The weight of sand is obviously much higher, and you cannot swim through it.
The old classic. Pit traps found in many ancient tombs are 20 feet deep, or more, so as to preclude easily climbing out witout assistance.
Liquid mercury may be used decoratively, as is rumoured to have been the case in some ancient Chinese tombs. The presence of the toxic metal liquid in such large quantities could be even more affecting than Cinnabar.
Another rumoured ancient Chinese trap, mechanical crossbows might stay functional for longer if they – and their strings and bolts – were made of metal. These are likely to be triggered by simple mechanisms such as doors, plates and switches.
While they might not mean anything to us today, in fantasy worlds curses may well have a genuine effect. Just something to consider.
An corridor angled upwards, a false flagstone. One false step and a great stone block crases down, squishing whoever set it off, then grinding down the hall under the force of gravity to lodge at the end, cutting off the corridor and the poor saps it has run over.
In more modern times punji stakes in pits have been ‘primed’ with faeces, and there’s no reason to think older spikes might be covered in similar nastiness. Disease spores can also last a long time, smallpox almost came back once because of a couple of scabs in an old book. Why not prime your tomb with disease?