What Could This Star Be?

It dimmed by 97 % for a few hundred days, and then came back up to full brightness. No planet passing in front of this giant star could reduce its light by 97%. Yet, tit's a big twinkle. It made all the stratumersto tinkleaafter observing it. And they've done some calculations. You know, if this thing is going to eclipse such a big star, it has to be huge.