Streetcap1 found this unusual astral phenomena captured by NASA’s Stereo Ahead satellite.
The event starts to take shape around the 1:00 mark but I would watch from the start as the video shows some of the beauty of space. But when you get close to the 1:00 mark, pay attention to the top right area where you will see some sort of expanding explosion.
Your first reaction might be to think it is the Sun, but you will see Streetcap1 notes the position of the Sun, so the explosion is NOT our Sun and is an unknown source.