I've watched that like 10 times and I cannot figure out how all of sudden the coils start forming and extending. What am I missing that makes that happen?

At first I thought electricity. But now I think it’s pressure from the bar of metal on the left. It has a curve at the end, and the blade on the right appears to be at a very certain angle. Together, the two forces act to extrude the wire at the perfect angle to make a spring. Just a theory.