What is the bizarre skin jewelry Kim Kardashian and Chrissy Teigen are wearing?

Kim Kardashian showed off on Instagram a choker in her skin color that looks like it was implanted onto her neck. The necklace is from A. Human, an experiential art exhibit and fashion line that explores body modification created by friend Simon Huck. Kim explained on her Story clip that the necklace lights up to the rhythm of her heartbeat.