So imagine that you’re talking to someone, and as you’re talking to him, his face sprouts horns, his mouth sprouts fangs, and his ears transform into bat wings, and they start flapping, and his head tears right off its body, turns around and starts drinking the blood that’s fountaining from his former neck-place. You’ve just witnessed the birth of a vargouille, a silly and horrible little fiend that’s the extraplanar personification of cooties.
Vargouilles are stupid and possess an underdeveloped survival instinct. Though birthed in solitude, they flock together as quickly as possible for the safety of numbers. They can drag themselves along the ground only feebly, but they can fly faster than the average humanoid can jog. They’re resistant to cold, fire and lightning damage and immune to all forms of poison, including the poisoned condition. They have 60 feet of darkvision and detest sunlight (although it doesn’t do them any actual harm, as it does to, say, kobolds).
With above-average Dexterity and Constitution (and nothing else), vargouilles are skirmishers; moreover, they’re flying skirmishers, which means they’ll often keep station 10 or 15 feet in the air, fly down to attack, then fly back out of reach. This makes them subject to opportunity attacks, which should matter, but with a Wisdom of only 7, they’re not prudent enough to try to avoid it.
The vargouille’s basic melee attack is a bite, which does a surprising amount of damage for such a low-level critter. However, it has two basic desires—to feed and to make more vargouilles—and the way it accomplishes the latter is through its “kiss.” The kiss transmits the vargouille’s curse to a recipient who fails his or her saving throw; however, for this to happen, the target has to be incapacitated.
This is where the vargouille’s other feature comes in: the Stunning Shriek action. Anyone who fails a saving throw against this action is frightened; any creature frightened by this action is stunned; and a stunned creature, by definition, is also incapacitated.
Stunning Shriek, like a dragon’s Frightful Presence, is one of those effects that either works on the first try or won’t work at all. Unlike immunity to Frightful Presence, immunity to Stunning Shriek lasts only for an hour. Within the context of a single combat encounter, however, it may as well be permanent.
Since Stunning Shriek is what enables the vargouille to use its kiss action, this is what it leads off with. It begins by flying into the midst of a group of potential victims—within 30 feet of at least six of them, or of the entire group if there are fewer than six—and letting loose its shriek. (If it’s just sprung from the head of its former body, it has no interest at first in anything except feeding, but it will immediately launch into its combat routine, beginning with Stunning Shriek, if its feeding is interrupted.)
What it does next depends on whether its shriek worked on anybody. If one of its targets is now frozen with fright, it zeroes straight in and uses its kiss on him or her, then flies up into the air. If the shriek affected more than one target, it simply goes for the nearest one. Vargouilles have no targeting heuristic beyond which victim they can get at first. They also have no time to kiss more than one victim, since the effect of Stunning Shriek wears off at the end of a vargouille’s subsequent turn and can’t be renewed.
If no one is affected by Stunning Shriek, or if the vargouille has already “kissed” its first victim, it switches to dive-bombing bite attacks, choosing its first target largely at random and afterward attacking whoever’s attacked it most recently, unless and until it’s moderately wounded (reduced to 9 hp or fewer). Vargouilles don’t expect that their victims will fight back in any meaningful way, and when one does, they panic and split, using the Dash action to fly away at double their speed (which may expose them to opportunity attacks).
Vargouilles follow this pattern even when they’re in a flock. Their behavior isn’t affected by their being surrounded by others of their kind. They’ll all let loose their Stunning Shrieks at once, they’ll opportunistically kiss a victim stunned by another’s shriek as often as one stunned by their own, and they’ll all fly away based solely on their own condition, not on the conditions of others in their flock.
Next: rust monsters.