Air carrier pilot reported a near miss during final approach to SFO Runway 28L with an object that appeared to be a cable-like structure hovering near the approach course.

Narrative

While on approach to land at San Francisco International Airport; I observed an unusual object hovering in the basin to the left of the final approach course for Runway 28L between Coyote Point and the airport. I was the pilot monitoring during the approach; and was watching intently outside of the aircraft as it was clear; there was heavy bird activity; and a possible drone had been reported in the vicinity of the final approach area. As we passed Coyote Point; at an altitude of 1100-1200 feet AGL; I saw an unusual structure" pass below and to the left of the aircraft; 100-200 feet below us and just outside of our wingtip. I reported to the Tower on landing that it looked like the cabling for a windsurfing kite; without the kite. The structure appeared to be a cable; in an upside down horseshoe shape; hovering in the air. There did not appear to be any sort of attachment to the ground. I keep a "cheat sheet" of all the important information for each flight; and while waiting in the penalty box for our gate to open up; I drew a quick sketch of what I had seen just before landing.I do not know what I saw; but it appeared to be cables of some sort. Given its size; apparent structure; and proximity to the approach corridor; I believe this device could be an extreme hazard to aviation. Almost like a lasso hanging in the air; if hit by an aircraft moving at 150-160 miles per hour; and depending on the mass it possesses; it could wrap around an engine nacelle; landing gear; or even a fuselage and cause significant damage to any number of aircraft structures including but not limited to tires; struts; flaps; primary control surfaces; and windscreens or other aircraft windows.Again; I will state that I do not know what I saw; but I will emphatically point out that whatever this structure is; it is a severe hazard to aviation. We cannot allow this thing anywhere near where aircraft are operated. This MUST be looked into immediately and dealt with or something catastrophic may occur."