A programmable one-use trap that summons two floor-local guards or minions after a two-second delay.
The traps around Fort Freedom are programmed to summon specific naiad guards. Because the were-castors have already killed those guards, accidental activations merely deposit their corpses on the hillside.
Carl collects ten devices after Find Traps reaches level 10. They can be programmed at a Sapper's Table, but will misfire unless the user controls a town or minions on the floor. Carl concludes that Donut would need to set them because she controls minions.
A concealed recycled trigger device that can be reprogrammed after disarming.
The trap is both a training obstacle and a potentially useful deployable summoning tool.