In 2014, ZeniMax sued Oculus VR on allegations that CEO Palmer Lucky had stolen technology that made the Oculus Rift VR headset possible, and it became a 4 year long battle between ZeniMax and Facebook once the latter bought Oculus VR. Finally, the suit has been privately settled for some amount of cash.
https://www.notebookcheck.net/ZeniMax-and-Facebook-finally-settle-over-4-year-long-Oculus-lawsuit.381196.0.html