Who invented the slinky spring?

The slinky was actually invented by accident by Dr. Francis Crick (of Watson and Crick fame).

While conducting an early study of DNA, Crick attempted to make a model of the molecule's structure using lab grade aluminium wire. The first model was made too narrow to allow the second helix to be inserted correctly so it was discarded. The lab technician working that day took the coil of wire out with the other rubbish but dropped it whilst walking down the stairs. To his surprise, the spring began to walk down the stairs of It's own accord! He called Dr. Crick who then came to observe the phenomena and they both had a good laugh at the delightful behaviour of the spring. Originally Crick wanted the spring to be known as the 'Crick curve' but he decided it was better to tie his name to DNA so instead he named it after the lab technicians cat, 'Slinky'.