Final answer:
The specific sound Ivan compares to "dancing water" is not provided in the text, but the passage describes a vivid auditory landscape, resonant of the free association technique used in surrealism, which is evident in Max Ernst's 'The Elephant Celebes.'
Step-by-step explanation:
The question relates to the description in the narrative where Ivan compares the sound to "dancing water." This metaphor is used to describe the rich auditory landscape that the character experiences, which includes the humming of gnats, the beating of dragonflies' wings, and the strokes of water-spiders' legs. There is no mention of an elephant joke or the specific sound Ivan compares to "dancing water" in the provided text. However, the passage does paint a vivid sensory picture of nature and its inherent music, evoking a sense reminiscent of free association similar to the technique used by the surrealist artist Max Ernst in his work titled 'The Elephant Celebes.'