What the hell is this thing?

A Slinky, or "Lazy-Spring," is a coil-shaped toy.
Slinkys come in various sizes, but are usually no larger than an ostrich egg when compressed. The shape is a simple helix, or coil design, of a ribbon of material, originally metal. The Slinky can "walk" down stairs as the coils stretch and reform as gravity moves them down each step.

Here is a nice performance with contortion and full of colors!