Soon filled the apartment. It was domestic thunder, The color of spinach.
The thunder, which started off softly, "soon filled the apartment." Maybe the Sea Hag did have something to fear, after all. Popeye is responsible for all this thunder.
The thunder is "domestic," meaning it relates to the home or family. "Domestic" is an adjective that has probably never been applied to thunder before, but in this poem it makes sense: everything here feels tame and domestic. A huge, exciting natural phenomenon has been reduced to something that fits inside a small apartment.
Moreover, this thunder is the color of spinach: green.
Popeye chuckled and scratched His balls: it sure was pleasant to spend a day in the country.
At last, we catch a glimpse of the man himself, the great Popeye! And what does he do to acknowledge his greatness? He laughs and then scratches his genitals. Not exactly out of character for a sailor, but for someone who can create thunder, we expected a bit more.
Popeye must have missed the memo about how dark and stormy it has become inside the apartment: he's perfectly happy to "spend a day in the country."
Nor is he very concerned about Olive's story about exile and family distress. He almost seems to live in a completely different world from the other characters. He has none of the dissatisfactions or concerns.
Thus, the poem ends on a humorous, somewhat vulgar, completely unexpected note of peace and contentment. Does this ending make you say, "Genius!" or "I want my money back!" or something in between?