An alien? An 'Iron Giant'? Some astronaut?
Well, the suspense seems to have been solved.
Weather experts say the phenomenon can be explained by what is called 'Fata Morgana' - a specific kind of mirage.
No wonder, throughout history, few phenomena have both fascinated and scared the hell out of sailors, saints, warriors and vacationers alike.
But Fata Morgana is great because of what it quintessentially succeeds at.
Over centuries, every Fata Morgana has attracted our attention, invoked curiosity, set our mental models in search of narratives that could explain it, and sent us on a great big, wild goose chase.
But all Fata Morganas have one thing in common. They all make complete sense once the underlying logic and rationale are brought to bear.
In modern marketing terms...
... Fata Morgana is like an ad that brilliantly grabs our attention, by the horns, but not like those click baits, or those that come with some cheap attention-grabbing visuals or effects.
Let's take Abby Wambach, for instance...
The 35-year-old superstar is said to be one of the greatest soccer players to ever step on the field. Besides leading her team to World Cup victory, she also won two Olympic gold medals, became the world's all-time leading goal scorer (man or woman), and was recognised as one of TIME's 100 in 2015.
On 16 December 2015 she played her final game in New Orleans. And on 16 December 2015 when she took the field for the last time, Gatorade released this commercial.
(The author is principal account manager, FMCG vertical, Google India. He blogs at brandednoise.com)