Characters
She won't be coming down here with the spray. She'll be coming down here with a shovel. It happened to my brother. Split him right down the middle. Now I have two half-brothers.
— Earthworm ‧ James and the Giant Peach

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker warns that a shovel, rather than spray, is the danger to expect, citing a brother allegedly split down the middle. The punchline gives half-brothers a grotesquely literal meaning. A family term becomes an arithmetic joke about dismemberment, turning the warning into dark comedy.
Context reviewed