President Donald Trump can’t resist taking a dig at North Korean leader Kim Jong Un, even when selling tax reform.

After calling the Republican tax plan “rocket fuel” for the American economy, Trump digressed with an aside on “Little Rocket Man,” calling Kim “a sick puppy.”

Trump drew hoots from the crowd during a tax reform speech in St. Charles, Missouri, with the impromptu shot at Kim a day after the North launched its most powerful missile yet.

Earlier Wednesday, Trump threatened additional sanctions against the North over its continued nuclear missile development.