The Spirits of Christmas play a part in Ice Station Santa.
When he became aware that the Shambling Corporate Presence had made its way into the workshop, Santa sent for the spirits in order to help contain it. Unfortunately this plan was marred when Sam & Max unwittingly unleashed the SCPs true form before the spirits were in position. To make things worse, the spirits would then only help Sam & Max clear things up after they restored the Christmases they've ruined; an obvious parallel with A Christmas Carol, with the difference that Sam & Max can actually act directly on the past and future they witness. After the Christmases are saved, the spirits manage to diminish the Shambling Corporate Presence to a plate of jello, then leave.
The spirits appear as floating ghostly apparitions looking much like Santa.