A rules option for GUMSHOE horror games
In situations where a Sense Trouble test might reveal the presence of danger from an otherworldly or eerie source, offer the players a chance to pay a price later in exchange for a benefit now.
One player gets an automatic success at a Sense Trouble test by agreeing to take on a Stability penalty that lasts for the rest of the scenario. Let’s call this a Stability Handicap.
In the typical situation in which Sense Trouble merely allows the element of surprise in a fight already guaranteed to happen, that penalty is -1.
If the test lets them entirely avoid a significant hazard or skip a fight with something nasty they don’t want or need to tangle with, the penalty rises to -2.
In the story, the moment represents a sudden flash of eerie awareness, attuning the recipient to eldritch energies. Depending on the situation, you might narrate:
a jackhammering heart
the nearly overwhelming urge to vomit
a jolt of rootless anxiety
an epiphany of cosmic dread
the appearance of a rash, welts, or other psychic injuries
an overpowering smell unsensed by anyone else present
an awful vision of monstrous violence that surfaces in the mind for a split-second and is then immediately suppressed
Make this a rare option, keyed to specific story events. You may decide that it only makes sense for characters already exposed to the supernatural, or those who have succumbed in some way to its influence.
Offer it only when the rest of the scenario holds out the possibility of at least 2 Stability tests.
The more physical symptoms for the Sense Trouble success might instead call for an Athletics or Scuffling Handicap. Instead of increasing your mental vulnerability, that rash that came out of nowhere makes it harder to throw punches.
For an additional fraught choice, you could even let the player choose which of the three abilities to Handicap. In that case you can allow the Handicap even if you aren’t sure that 2 or more tests of each ability still remain in the scenario. Correctly predicting which Handicap will hurt the least becomes part of the player’s challenge. Here the cost lies in the anxiety of decision making as much as in any actual penalties dished out in later scenes. If players always guess right, and Handicaps start to feel like a free gift, make sure they pay the piper next time around. See to that a penalty happens, in a situation with truly harrowing stakes.