Mad Piper

A grey mound of flesh scuttles forward on mismatched limbs, its five heads trilling along on bone flutes. All the while, a harrowing tune plays from the column of pipes rising from its core._
Mad pipers are the heralds of the Great Old Ones, a sign that a cult is getting close to achieving their goals. Cultists receive visions from their masters, filling their dreams with the esoteric rituals needed to create a mad piper. In short order, the cult gathers the components and creates these creatures, typically one for each cell of the cult. When the time comes for the cult to do battle, the mad pipers follow, inspiring the faithful with the alien songs of the Great Old Ones.
The Ritual. During the ritual, five humanoids, one of which must be a musician of some kind, are tied to a set of bagpipes made from an ogre’s bones and stomach. The ritual liquefies the humanoids, who fall into each other as all but their limbs and heads dissolve into a mass of grey flesh. Their minds, souls, and bodies forcefully merged, they start to play.
Pets and Mascots. Mad pipers aren’t naturally evil. Most are made from commoners, resulting in relatively docile and loyal creatures that imprint quickly onto cult members, who in turn often come to treat these abominations as pets. More violent and powerful mad pipers can be made from powerful, evil humanoids, though they are harder to control and often hostile to their creators.
True Pipers. Scholars speculate that the mad pipers are modelled after the heralds of the Crawling Chaos, and that it was he who gifted the first ritual to mortals on behalf of all Great Old Ones.
Construct Nature. The mad piper doesn’t require air, food, drink, or sleep.