Obviously, Santa is a timelord who has assumed the identity of Saint Nicholas of Myra. This explains why he can live forever, why he appears differently to diff

Obviously, Santa is a timelord who has assumed the identity of Saint Nicholas of Myra. This explains why he can live forever, why he appears differently to different children using psychic paper (skin color, clothing, shape, different names, etc), can enter homes without chimneys (Tardis disguised as a sleigh) and why his sack is bigger on the inside than the outside. The Doctor isn't the only timelord who has an affinity for earthlings.