Chthonous burl

In “Memories of My Father Watching TV”, Curtis White writes:

“Once in his reach, Neal would take a horrible chunk of heavy metal, like an iron pineapple, like an icon of some unconscious horror, out of the car trunk.
(An old question resolved: the location of the unconscious is the car trunk.)
…Perhaps once this thing had a mundane function, but rust had melted the angles away and now it was just a massive object that seemed to beg people to use it for murder.”
(Or perhaps it was something plumbers had excavated from the bowels of my sewage system… . I had this conversation with the plumber: ‘Well here’s the problem, mister.’ ‘My God, what the hell is that thing? How did it get in my soil pipe?’ ‘Beats me.’ he rolls the snotty tumor around in his crusty hands. Of course, I knew darned good and well what I wouldn’t tell the plumber, that it was something from my brain that had floated loose and had been circulating in the house system for months, finally coming to rest in the pipe leading to the community sewer.)

[…]

…I would happily have killed my father with the chthonous burl of iron…