I know, I know — “slippery slope” is pretty cliché. But it seemed to work here. The strained and inverted syntax is supposed to reflect the opposing forces of gravity and the climber’s desire to get to the top of the dune. I’m not sure it works; I confess my choices were dictated by what I could draw. What I had verbally sketched out was
…And gnashing teeth —
Lodged in a lethal throw
The slippery slope she barefoot treads
Up the oil-slicked dune…
But I didn’t know how to draw “disgusting” on its own.