Well, this certainly looks like a K’tonian artifact but if you notice the grooves on the bottom, that means that this was actually made on a Jiyong potters wheel as an imitation of the K’tonian style of pottery. This is a replica, albeit a 700 year old, very good replica. I do happen to know a buyer who would be willing to pay you for it.
A wizard has cast a slow action freezing spell upon a PC. The air gets colder around the PC by one degree a day. If the spell is not broken within a few weeks the PC will freeze and die.