Don't forget your sunglasses around ASASSN-15lh 
"The light source, named ASASSN-15lh, was initially categorised in the US in 2015 as the brightest supernova (exploding star) ever seen.
However, QUB Professor Stephen Smartt, said: "We observed it and thought: 'Nah, it doesn't look like a supernova to us.'"
http://www.bbc.co.uk/news/uk-northern-ireland-38292733
"The light source, named ASASSN-15lh, was initially categorised in the US in 2015 as the brightest supernova (exploding star) ever seen.
However, QUB Professor Stephen Smartt, said: "We observed it and thought: 'Nah, it doesn't look like a supernova to us.'"
http://www.bbc.co.uk/news/uk-northern-ireland-38292733