Curse of the beast lord/Princes of hell.
Hiricine's Puzzle Box
This puzzle box was found in an abandoned church outside of Innistrad, where the party of Cyrus, Gabrielle, and Sebastian went in search of a 12-year-old boy named Lance. After defeating evil clerics and nagas, Sebastian found a strange box on an altar and asked Cyrus to examine it. Cyrus played with it for a few minutes before reading the inscription “May the will of the Beastmaster be praised;” which led to the box expelling a cloud of pink mist that the adventurers had no choice but to inhale. Not long afterward all of them left feverish and passed out only to wake up with… “new features.” This is what turned the group into lyncathropes.