What IS that thing, anyway?

[Snagg]

Thanks fer yer answers - this is in a spot right near the joint where the thigh meets the drumstick, and there are no signs of veins or anything that I would expect to be servicing a major organ like a kidney or lung or anything; I'm thinking the "Blood Pudding" answer might be the closest to what I'm talking about, because it slips out very easily - there doesn't seem to be any kind of stabilizing connective tissue or ligament. Just a mass of dark meat covering over the little cavity. Although the idea of a little pool of loose blood, not contained within any capillary system does seem strange......

Oddly, it also seems to retain a bit more mass when roasted or boiled, while frying seems to reduce it's volume somehow. Weird........