(definitions from Dictionary.com)
11. Metallurgy. a. a ridge of metal left on a casting by a seam
between parts of the mold. b. a ridge formed at the edge of a forging or weld
where excess metal has been squeezed out.
What forms from squeezing
out excess; what is left after compression. Imagine here perhaps of what
remains after a story’s been casted; imagine the part someone thought didn’t
matter. Imagine it is.