Who is Santa Claus? A jolly little old obese elf who flies in a sleigh with magical reindeer once a year, bringing toys to all the good boys and girls in the world? Perhaps the better question would be, what is Santa Claus?
Have you ever stopped to drop your spare change in the little red bucket by the bell ringers? Have you taken notice of all the needy "angels" hanging on the angel tree at the store? Have you seen the rescue mission/soup kitchen on Christmas? Each of these is Santa Claus. Each one is a manifestation of human kindness. No one should be without on Christmas. If only for one day, we should be surrounded by the true love of Christ: warmth, kindness, and care.
Santa is the embodiment of all these things. He sees to it that no one goes without. He wishes all well. He loves all with a perfect Christlike love. So who/what is Santa Claus? The best of human nature wrapped in the sweet spirit of giving.