Shaggamaws

Feverlings derive a large part of their subsistence from residues of the chaotic energies which gave them form, whether absorbed directly from errant currents or scoured with rough tongues from the bottom of abandoned flasks and cauldrons. A perhaps more expedient method of gathering these vital energies would be to move a step up the food-chain, from gathering to preying upon those that do. On occasion this idea will occur to a feverling and lead them to acts of cannibalism.
Feverlings who feast on others of their kind grow rapidly and out of all proportion to their kin, often ceasing to be recognizable as being of the same brood or even species. If the offending member is not slain, either out of collusion or cunning on its own part, the creature will grow into a dangerous being known as a shaggamaw (stats as ogre + a 1d8 bite option), its maw widening terribly as its bulk increases. Small bands of such creatures can form for mutual protection and to aid in predation, and on rare occasion a brood will intentionally allow the formation of one or more within their own ranks, using members of rival groups to fuel the transformation.

Another Jody Siegel piece - shaggamaw