Residents of Rio de Janeiro were left bemused by the appearance of a series of unidentified signs and circles on the face of Sugarloaf Mountain on Sunday night.
As darkness fell, witnesses reported seeing a green laser beam fired from an unknown location onto the 396m mountainside overseeing the Atlantic Ocean.
The beam gradually enlarged to form scrambled symbols which gave the impression of an encrypted message. "What does it all mean?" asked one stunned bystander. "Why is this happening?"
The encoded letters increased in brightness before settling into the shape of a gigantic logo. It resembled a giant circle with a football shape carved into the centre of the image.
Rio is due to stage key matches and the World Cup final next summer but it is not yet clear what connection this unexplained incident has to the sport.
The mysterious hologram remained illuminated on Sugarloaf for more than two hours before finally fading, at which point wording appeared clearly stating: #winnertakesearth.
The unusual scene also prompted passing drivers to reduce their speed and residents to flock to the edge of the oceanic Guanabara Bay. It was not long before the discussion spread to Twitter where grainy photographs were posted.
Maria Clara Rocha, 27, said: "I have lived in Rio all my life and I have never seen anything like it. It was very eerie and spooky. I really want to know what this all means."