Interestingly, 'flaming wreck' could only be used to describe the Sinspawn for a few moments, as it staggered around before it finally gave over and died. The corpse however, didn't stay around nearly as long as one might have expected, vanishing into a myriad of of fist-sized points of multicolored light. Pyreflies, although the term was unlikely to be among the assorted terms that Harry was familiar with.

The general concept though, he might be able to guess at, as they floated their way up to the 'ceiling' of the domes, a soft haunting melody following them as they went. They were, in essence, the souls of the dead, now released from the anger and rage that had been their bond to Sin, and the fiend's body they'd worn.