Exocomet hypothesis or alien mega structure?

Astronomers have spotted an object in space that blocks a surprising amount of sunlight, leading to speculation it could be a massive structure built by aliens.Many astronomers have been speculating it's alien in design. But now the exocomet hypothesis is becoming more likely.

After all the kerfuffle surrounding a certain star scrutinized by NASA’s Kepler Space Telescope last October, astronomers have been feverishly trying to find a, um, natural explanation for a bizarre transit signal. Though it has turned into something of an epic endeavor, astronomers are zeroing in on the most likely candidate.
Watch this video from CBS news. What do you think? Is it possible that there is an alien super structure 1500 light years away? http://www.cbsnews.com/videos/have-astronomers-discovered-an-alien-megastructure/