Trap Generation and Placement
The trap generation chart below is not an exhaustive list. In fact, a quick perusal of this chart should readily produce several variations on the themes presented herein. It should also be noted that some traps can be combined to great effect. For instance, a spiked pit trap might trigger a swinging log to "help" the players in. Use your imagination.
There are various possible trap levels appropriate for different situations, as follows:
Nuisance: A hidden trap door with a 10-ft drop.
Hazardous: A hidden trap door with a 10-ft drop onto spikes.
Dangerous: A hidden trap door with a 10-ft drop onto poisoned spikes (for extra nastiness, have the pit lock shut after the victim falls in).
Fatal: All the above plus a 10 ton stone block the exact shape of the pit that drops down from the ceiling into the pit.
Generally traps should be suited to the dungeon level on which they are situated and the potential treasure they guard. Thus a trap on the first dungeon level that leads to an area infested with ferocious but poverty-stricken monsters should be nuisance, while a trap on the sixteenth dungeon level that protects a pair of dragons' treasure hoard while the dragons are out hunting should be fatal.
Intelligent creatures that live near a trap will always have some means of avoiding or disarming it—whether this be an alternative route they habitually take or some mechanical or magical means of bypassing it. If they use the trap to protect their lair, treasure or young, they will maintain the trap to the best of their ability (perhaps cleaning away bloodstains or other evidence of its existence, for example). And if the player characters learn to bypass the trap, intelligent monsters may try to find a way of making it effective again—perhaps by moving it or adding additional features, according to their ability and resources.
When placing traps, think about their purpose in the game and the effect they will have on playing style. Traps are there to increase "the risk of dungeoneering and to encourage skilled play; good dungeons have a judicious mixture of monsters, traps and roleplaying encounters.
Let's consider two OSRIC GMs. One likes to use many traps, some of which cause instant death with no save, while another prefers to use much fewer traps and always permits a saving throw.
The first GM's players will adapt. They will move slowly and carefully through the dungeon, and may have summoned creatures or created zombies to move ahead of them; triggering any traps they might encounter. They will tend to capture prisoners and question them under //charm// or some similar magic about the dungeon environment, and evil aligned characters may use captives like mining canaries. The pace of play will be slow owing to the characters' caution.
The second GM's players will tend not to be thieves. They will move more rapidly through the dungeon to try to achieve surprise against any foes they might encounter, and the game will have a more heroic feel to it.
Decide which style of game suits you and your group and design traps in your dungeons accordingly.
Random Trap Generation
|1-2||acid spray||51-52||oil-filled pit with dropping lit torch|
|3-4||bolt, crossbow||53-54||pit trap triggered by false door|
|5-6||bridge, collapsing||55-56||pit with dropping ceiling block|
|7-8||bridge, illusory||57-58||pit with locking trap door|
|9-10||caltrops drop from ceiling||59-60||pit, 10-ft|
|11-12||ceiling block drops behind players||61-62||poisoned bolt, crossbow|
|13-14||ceiling blocks drop in front of and behind players||63-64||poisoned caltrops|
|15-16||ceiling block drops in front of players||65-66||poisoned spear, ballista|
|17-18||ceiling block drops on players||67-68||poisoned spike pit|
|19-20||ceiling block seals players in room or area||69-70||portcullis drops behind players|
|21-22||elevator room||71-72||portcullises drop in front of and behind players|
|23-24||elevator room, deactivates for 24 hours||73-74||portcullis drops in front of players|
|25-26||elevator room, one way||75-76||rolling stone ball, height and width of corridor|
|27-28||falling door||77-78||scything blade, ankle-high|
|29-30||flame jets||79-80||scything blade, neck-high|
|31-32||flooding room||81-82||sliding room changes facing or location|
|33-34||gas, blinding||83-84||spear, ballista|
|35-36||gas, fear||85-86||spiked log trap|
|37-38||gas, flammable||87-88||spiked pit|
|39-40||gas, sleep||89-90||spring-loaded pile-driver disguised as a door|
|41-42||gas, slowing||91-92||stairs fold flat into a sliding chute|
|43-44||greased chute||93-94||stairs collapse|
|47-48||log trap, swinging||97-98||trip wire|
|49-50||obscuring fog||99-00||wire, neck high|
Tricks make something harmless appear dangerous, or make something dangerous appear harmless. Create an expectation but fulfil it in an entirely extraordinary manner: an expensive diamond ring resting in a sturdy lead coffer, or is it? The ring is a well made but worthless trinket, the box is solid gold painted to appear as lead. This is the essence of the trick. Use the two tables below to generate random tricks. The first table will generate a mundane object commonly found in most dungeons, and the second will provide an unexpected attribute.
*Any: jar, box, coffer, chest, barrel, vase, casket, etc.
**Any door: secret, concealed, valve, arch, etc.
|8||changes minds from one body to another||58||magnetic|
|9||changes sex||59||makes younger|
|13||decreases Charisma||63||opposite alignment|
|15||decreases Dexterity||65||plays games|
|23||dispenses counterfeit coins||73||resists magic|
|24||dispenses counterfeit gems||74||reverse gravity|
|25||dispenses counterfeit jewellery||75||reverse wish fulfilment|
|26||dispenses counterfeit magic item||76||riddles|
|27||dispenses counterfeit map||77||rising|
|30||dispenses magic item||80||shoots|
|40||flesh to stone||90||takes|
|42||fruit||92||talks in poetry and rhymes|
|44||geas||94||talks very intelligently|
|45||gravity decreased||95||talks, spell casting|
|47||greed inducing||97||unusual colour/texture material|
|49||increases Charisma||99||wish fulfilment|
|50||increases Constitution||00||yells and screams|
Example of use: Gina the GM needs a trick to round out a dungeon map. Taking her trusty d% in hand, she rolls a 37 on the feature table and a 55 on the attribute table. This yields a result of idol, intelligent. She decides the room will contain a carved idol which holds the mind and soul of a long departed adventurer. The idol knows something of the surrounding dungeon rooms but not much else. Depending on how the party approaches and treats with the idol, it may relate some of its knowledge to them.
Gina decides to roll a second trick for a different room and rolls a 25 then 31, which yields a result of fireplace, dispenses map. She places an unlit fireplace in the room in question that has a rolled up map of the next level down hidden among the logs stacked neatly within.