It's still not an alien megastructure, but the strangely-dimming sun known as Tabby's Star isn't being occasionally occluded by comets.
KIC 8462852, to use its formal designation, gave
UFO-spotters a veritable hypegasm last year, because the odd
fluctuations in its brightness were hard to explain.
When Penn State University boffins used Tabby's Star
as an example of the characteristics we might expect of a star
surrounded by a Ringworld*-like megastructure, the headlines went crazy. Killjoys at NASA damped that down in November, saying it's more likely that the start twinkles because it's orbited by a swarm of comets.
Comet halo theory for flickering 'alien megastructure' star fails • The Register