An older person wearing a red Christmas (aka "Santa") hat. Does not represent any specific character in folklore. Mx Claus provides a gender inclusive alternative to 🎅 Santa Claus or 🤶 Mrs. Claus.
Mx is an honorific that does not indicate gender.
The Mx Claus emoji is a ZWJ sequence combining 🧑 Person, Zero Width Joiner and 🎄 Christmas Tree. These display as a single emoji on supported platforms.