What is the suprising thing that happens in a superconductor

One of the most surprising things about a superconductor is that

it has NO electrical resistance. The resistance doesn't just become

very very very small. It becomes literally completely zero. (This is

a big part of the reason why it's called a "super-conductor".)

If you start an electric current flowing in a superconductor, you can

connect the ends of it together, and the current keeps going around

and around the loop and never dies out!