You approach the structure cautiously; some kind of crystalline shell around a stiff skeleton. There's no sign of life, but the doors slide open as you reach them. As you step inside, there's a sudden roar, and a wave of searing heat blasts down from overhead. You stumble, but thanks to the warning noise, you roll aside to safety with only minor blisters. Glancing up, you see a tell-tale grille above the door.
Recovering from your initial shock, you look around cautiously. Still no life. Angular machinery hangs on the walls; some kind of monitor, or another weapon, it's hard to tell. You start to move down a narrow hallway, and must've triggered another alarm, because your biosensors go into overdrive. There's a strange stuttering noise above, and your sensors flare with radiation warnings: get out of here NOW!
There's a door nearby, and you fumble with the controls until it finally swings open. It's deafeningly loud, and brutally hot, but the door seems thick enough to keep out the deadly rays. By the door you see some kind of control, but a quick glance shows a cable linking it to another of the ray-tubes overhead. Rather than take a chance, you fire a pellet at it, shattering the tube. Safe. A tall, cuboid object nearby is the source of both heat and noise, and you huddle away from it while you slap on some radsalve. Immediate injury dealt with, you spot a cable hidden behind the box, linking it to a wall-socket, and deduce that it's either a power source or a data line. Worth a try. You tug out the cable, and the hum dies away. Prying open the box, a wave of blessed coolness pours out. Some kind of chemical cabinet? A row of containers holds an opaque fluid with a harshly acrid stench. Several waxy blocks are wrapped in preservative foil. Examining the box itself, your hearts stop for a moment as you spot the device wired into the door. If you hadn't cut the power, it would have triggered right in your face.
Exploring the rest of the building is slow progress. The builders were desperately paranoid. You try cutting the power, but that sets off a secondary defence that bathes the whole place in radiation. A few minutes of that and you'd be a goner. Finally, you give up and resort to drastic methods, entering each room with great caution and shattering the tubes from the doorway. In a hallway you find a humming box with an intriguing array of buttons, presumably a public datacore. Unfortunately, it quickly becomes apparent they've warded that too. Trying a couple of buttons, you hear a shattering growl, and leap back out of range. Just where you'd had a hand ready for the interface, a stream of fluid sprays out, so hot it's just a glowing line on your HUD. Hot enough to maim you for life, and most likely leave you half-dead with shock. These people mean business. You're not ready for this. Time to leave.
That probably wasn't very subtle, but here's a quick rundown of the hazards our heroine faced:
- An over-door heater triggered by either the door opening, or motion
- Fluorescent lights in the foyer, triggered by motion.
- Another one linked to the kitchen light switch.
- Some deadly, acidic orange juice, alongside milk and butter in the kitchen fridge.
- The fiendish internal fridge light, triggered by opening the door, thankfully disabled.
- Emergency lighting, triggered by tripping the power switch.
- And finally, the terrifying hallway coffee machine.
If you happen to be a species that's vulnerable to high-intensity radiation in the human-visible spectrum, that has a preferred temperature significantly below our own, or a substantially different skin pH, then perfectly simple things like heating, lighting, food and drink can make just wandering around my workplace an expedition fraught with unintended danger.
Similarly, apparently innocuous substances might be disastrous to different metabolisms. A pine-scented air freshener, perhaps. Chocolate, onions or grapes mixed in with a ration pack. Salt. Alcohol hand gel in a dispenser by the door. Even traces of cleaning substances - perhaps an unexpected plausible source for our good old friend the Doorknob Smeared with Contact Poison?
A spell designed to keep a building's occupants nice and cool might freeze the wrong species to death. A personal gravity system might crush them. A spell that keeps humans cheerful might drive Martians insane. A household spell to politely remove your hat and coat might tear chunks off the wrong species, while one to dry visitors off might dessicate them. I already mentioned that an ambient spell to speed healing might be disastrous, forcing metabolism to unsuitable speeds or affecting organ function.
A last few oddball suggestions...
- Timer alarms or ringtones set to a resonant frequency that harms crystalline beings?
- Surfactants that disastrously disrupt protoplasmic creatures?
- Dangerous magnetic fields from a pocket compass?
- Sudden radiation bursts from a phone or similar gadget?
So maybe that might suggest some origins for anti-human traps, which helps to work out how they actually function, how they relate to other parts of the environment, and how PCs might deal with them.