There were two separate experiments. In one, "Here we report such an experimental demonstration, with the moving bodies being two massive micromechanical oscillators, each composed of about 1012 atoms, coupled to a microwave-frequency electromagnetic cavity that is used to create and stabilize the entanglement of their centre-of-mass motion"- from the abstract.
https://www.nature.com/articles/s41586-018-0038-x