There's a chance it could be some previously unknown phenomenon, like how when pulsars were first discovered. If it were a dyson shell, like the pic below, that would block the light in "complex" and strange patterns:
$this->bbcode_second_pass_quote('', 'A')RE THOSE REALLY ALIEN MEGASTRUCTURES? HOW ASTRONOMERS PLAN TO INVESTIGATE
THERE'S SOMETHING WEIRD HAPPENING AROUND A FARAWAY STAR.

Illustration of a Dyson Shell
Siemion and his colleagues Jason Wright and Tabetha Boyajian think there's a chance that a structure like that could be blocking the light from KIC 8462852.
And it wouldn't necessarily have to be solar panels either, says Wright. If there's a structure there, it could be a telescope or some sort of habitation.To test their hypothesis, the team hopes to listen for the tell-tale signs of life around KIC 8462852. They've applied for time on the Green Bank Telescope in West Virginia. They'll be competing with other scientists who want to use the giant telescope to answer other research questions. If their application is selected, next year the team will point the telescope's 100-meter dish toward KIC 8462852 and scan the radio signals emitting from that region.
“If we heard narrow-band modulated radio emissions coming from that star, I can't imagine any other explanation,” says Wright, an astronomer at Penn State. No known natural phenomenon creates a radio signature like that.
...
Jon Jenkins from the Kepler team says he's never seen anything like what's happening at KIC 8462852, but "it’s not unusual for new phenomena to be greeted with an explanation calling for extraterrestrials that later prove to be due to more mundane but novel natural phenomena."
Siemion himself points out that when the first pulsar was discovered in 1961, it was given the designation LGM-1, for “little green men.” Like lighthouses of the universe, these rotating stars emit radio waves and other electromagnetic radiation at regular intervals.
http://www.popsci.com/alien-megastructures-how-astronomers-plan-to-investigate