Soucouyants

"One might mistake them for old women, until they discard their skins. The place is aswarm with them. They are strong as strangling roots, and at least half-Long, but they can be deceived, and they are very wary of light."

- In-game text

 is an Obstacle appearing during Expeditions. Its Aspect is Guardian. Interestingly, Soucouyants only appear in the Raven Isle vault. They represent Alukites.

Defeating
"The night air rattles with them. Duck low. They are much too strong to be fought, but we may be able to deceive them, or drive them off with Mansus-light."

- When confronting the obstacle

As hinted by the description, Followers with or  aspects can overcome this Obstacle with a probability depending on the aspect magnitude.

"They won't come close. They call out taunts in the voices of carrion birds and children; they rattle the tree-tops; they fling stones from the dark. But they won't come close. We will pass."

- After success.

We call upon the Watchman,...
 * 1 < < 5: ... who navigates. It is possible the power we carry will see us safe through the crowded night. It's definitely possible. 30% chance of success.
 * 5 <= < 10: ... who is not compassionate. Our power should be enough to hold them at bay - but they are ready for any lapse in vigilance. 70% chance of success.
 * 10 <= : ... who illuminates. We have power enough to keep them at a distance. 90% chance of success.

"Hurry from the shadow to deeper shadow. Press faces into the spongy earth. They know we're here, but they don't know where. Their cries fade behind us."

- After success.

We call upon the Moth,...
 * 1 < < 5: ... who is dappled. The Moth will give us a chance in the dappled shadows of the forest - but only a chance. 30% chance of success.
 * 5 <= < 10: ... who beats in the skull. We should have power enough to deceive and dismay these night-winged thirsty ones. 70% chance of success.
 * 10 <= : ... who seeks among the trees of the Wood. The Moth has power in this close-crowded forest night. We will pass secretly and safely. 90% chance of success.

Failure
"They're on us! With a leathery crack of wings, and a body is borne shrieking up into the dark -"

- After failure

Failing to pass safely through the Soucouyants has a 70% chance of injuring a Follower.