Prometheus tugs on Saturn’s F-Ring. Here’s how the Cassini site describes it:
The striated appearance of the F ring is immediately apparent in the region of the ring that trails behind the moon Prometheus. The F ring is characterized here by dark gores that stretch inward toward the planet and forward in the direction of motion.
This image has been expanded in the horizontal direction by a factor of five in order to make radial variations more prominent. The curvature of the rings is also exaggerated by the horizontal stretch.