The complete statement is "the old vine is faint, and the monkey moves the stool." This sentence is unconventional and continues the meaning of the previous sentence, creating a funny scene.
"The Dead Vine and the Old Tree Cry" is a poem describing natural scenery, which describes desolate, silent and silent scenes. But the next sentence, the monkey moving the stool, is completely out of tune with the previous sentence in the situation transformation, which brings unexpected funny effects.