Typed in a summary of an encounter from the Deck of Encounter - An example being "Airy Guardian" - Area: The location is an underground tunnel. It can be any tunnel that the PCs are about to enter. Situation: Before the PCs set foot in the tunnel make Wisdom or Intelligence check, whichever is lower. Those who succeed see a ripple effect, much like heat shimmersfrom the sands during the noonday sun, although there is no heat in this place. They also see something that looks as though it has been eroded into the floor by a fierce wind. Though the erosion is very slight, the words "Past the raging wind" may be faintly read.
The ripple is, in reality, an invisible stalker, ordered to guard the passage from all except those who have the right password. If the PCs notice the carved rock but do not say anything, the stalker will attack any who step into the passageway. If the words are spoken the stalker will withdraw. It avoids combat if at all possible, but will mess with the PCs by tossing their hair, swirling their cloaks and loose clothing, and being generally irritating