What If a Black Hole Ate the Sun?

It's almost as old as the Universe, and as massive as 34 billion Suns. It eats stars for breakfast. And now it's about to consume our own. Behold, the great and powerful black hole with the catchy name J2157. If it came close enough to our Solar System, how fast would it destroy us? How would it all go sideways for our Sun? And how exactly would this monstrous black hole end all life on Earth?