Mysterious 'black ring' spotted in the sky

A mysterious black ring of smoke was seen recently in the sky in Pakistan's Lahore.

A video of this unusual O-shaped "black ring" floating overdrew a flurry of reactions, social media especially on Twitter and shocked many, reports NDTV.

Some people called it an evil cloud while others simply saw an alien angle in it.

Watch the unusual thing that left many bewildered:

The video has been viewed over 37,000 times since it was shared online. It left a number of Twitter users convinced that there was something otherworldly about the black ring. Some others shared videos of similar black rings appearing in the sky at other parts of the world.

However, there is an explanation for the strange phenomenon. According to The Sun, the black smoke ring could have been caused by an industrial fault on the ground.

The smoke vortices were likely created by small combustion of the explosion - or a blast through a circular structure. Such circular smoke vortices have appeared several times before. In 2014, for example, the mysterious black ring in the sky over Leamington Spa in UK was eventually traced to a fireworks test.

A nearly identical smoke ring was also spotted over Chicago in 2012. It appeared due to an electrical transformer that blew up.