Well, or so I was told.
Our priest uses the vigil mass as a children's mass. He asks all of them to come up during the time of the homily and reads a story from a picture book to them. He then talks to them about the story and the Liturgy of the Word. Right at the end of the mass, "santa" brings up the bags of canned goods that the kids have brought for our local rescue mission and leaves them at the nativiy set.
No, I've never had a priest do that. The closest I've heard is
Wife to Scott
Mom to: Madeleine, James,
Santa is never mentioned in church.