The excerpt below is an example of figurative language from the short story "Rikki-Tikki-Tavi" by Rudyard Kipling. When he had lifted one-third of himself clear of the ground, he stayed balancing to and fro exactly as a dandelion-tuft balances in the wind, and he looked at Rikki-tikki with the wicked snake's eyes that never change their expression, whatever the snake may be thinking of.

What purpose does the bold-faced figurative language serve?