Scientists are absolutely floored by something they’ve found in space that they are struggling to explain. While scientists first discovered Tabby’s Star, KIC 8462852, back in 2015, they’ve been struggling ever since to explain it’s bizarre behavior. And now, the star is behaving strangely yet again.

The star is situated about 1,400 light years from Earth, and it’s been going through sudden dimming episodes that seem to be completely random. Scientists aren’t sure what to make of it, and some of the more outlandish theories suggest an alien megastructure like the Dyson sphere that has appeared in science fiction throughout the years. The star is back in the headlines after going through yet another dramatic dimming phase.

While dimming is not uncommon for stars due to planets or clouds of dust passing in front of them, these happen on a regular schedule, whereas this appears to be totally random. Also, the dimming is much more dramatic.

“A star known by the unassuming name of KIC 8462852 in the constellation Cygnus has been raising eyebrows both in and outside of the scientific community for the past year,” reads a statement from the Carnegie Institution for Science’s statement last year. “In 2015 a team of astronomers announced that the star underwent a series of very brief, non-periodic dimming events while it was being monitored by NASA’s Kepler space telescope, and no one could quite figure out what caused them. A new study from Carnegie’s Josh Simon and Caltech’s Ben Montet has deepened the mystery.”