Mary Christmas was the wife of Santa.
One day Mary caught Santa with Iris Wildthyme on his sleigh and presumed that he was having an affair. Mary kicked Santa out and plotted to get her revenge on Iris for stealing her husband. Using Clockworks technology, Mary pulled Panda out of the time vortex and drugged him to find the location of where she would be able to find Iris. Iris however had already found Mary and Iris regressed Mary's mind back to a time when she and Santa were happy and she let Santa move back in. (AUDIO: The Claws of Santa)