From publisher blurb:
This particular installment of Exotic Encounters focuses on the vargouille. These strange bodiless fiends date back to the first edition Monster Manual II, and are one of the stranger creatures of the lower planes, feared far and wide for their deadly kiss, which provides a very unforgiving “save or die” experience at a very low level, a terrible fate that is only compounded by the fact that the transformation is detailed in particularly macabre fashion as the character’s hair falls out and their facial features slowly twist over the course of one or more days. The first vargouille in this book, the singing vargouille (CR 3) can also cause such a transformation, though in this case, it is done by a haunting lullaby, instead. Singing vargouilles can also unleash powerful and damaging sonic shrieks, and their bite inflicts a curse of silence. These terrors pale before the bloodsucking vargouille (CR 5) however, which does not kiss its victims but instead attaches to them and drains their blood, transforming their victims into wights, whose heads separate from their bodies and become vargouilles when they are destroyed. Finally, the giant vargouille (CR 7) is a vargouille of titanic proportions, with a propensity for swooping down and swallowing human prey whole in a single gulp, and either allowing them to be digested by powerful acid that inflicts difficult-to-heal wounds, or simply spitting them back out again in the air, leaving the victim to fall to his doom.