Which archetype is the snake in this passage most likely based on?

when i turned, he was lying in long loose waves, like a letter 'w.' he twitched and began to coil slowly. . his abominable muscularity, his loathsome, fluid motion, somehow made me sick. he was as thick as my leg, and looked as if millstones couldn't crush the disgusting vitality out of him. he lifted his hideous little head, and rattled. i didn't run because i didn't think of it—if my back had been against a stone wall i couldn't have felt more cornered. i saw his coils tighten—now he would spring, spring his length, i remembered.
(from my antonia by willa cather)