Dammit, I told uncle Marty to stop blowing smoke rings!
I think it looks like a rather friendly ring, as opposed to an ominous one.
There used to be a billboard in Times Square which advertised "Camel's" cigarettes by blowing smoke rings over the crowded sidewalks. The rings were produced by a smoke generator which feed smoke into a box built into the sign. It had had a circular hole in the side of the box which was aligned with the smoker's mouth facing the street, opposite the hole the box had a flexible membrane which was struck rather like a bass drum except the "drummer" was a motor driven cam. The membrane produced a pressure pule when struck which propelled a smoke ring into the air over the street.
I've seen similar phenomenon as dolphins were playing in a large tank of water by expelling air from their mouth which produced a ring of bubbles which formed a rotating torus that held together as it moved a surprising distance. The dolphins would chase after the ring and try to catch it with their heads. It looked like children playing "ring toss".
You can make a smoke generator by carefully opening a pack of cigarettes and slide the cellophane wrapper about halfway off the pack. Use a lit cigarette to burn a hole through the cellophane about half way between the bottom of the pack and the closed end of the wrapper. Blow some smoke through the hole to fill the cellophane chamber, set the pack down on a flat surface with the hole facing up. Gently tap the cellophane away from the hole, you should see a smoke ring with each tap.
When the cellophane is tapped it propels smoke filled air through the hole where the particles commence to rotate about the annular axis of the torus and also move directly away from the source.
I haven't a clue as to why this seems independent of the medium (smoke, air bubbles, &c). There have been sightings in the south west of high altitude jet contrails described as "a string of pearls". UFOlogists have advanced the theory that USAF was testing the Aurora (next generation Mach 7 aircraft). They might actually be right for a change!
Regards,
GtG