Santa suit

A Santa suit, or Santa outfit, (TV: Last Christmas) was a distinctive red and white suit which was associated with Santa Claus. (COMIC: Holiday Special)

While operating on Earth at Christmas time, the Roboforms disguised themselves using Santa suits and masks. (TV: The Christmas Invasion, The Runaway Bride)

Danny Pink dressed as Santa Claus on Christmas Day in a dream crab-induced dream Clara Oswald was in. When she asked what day it was, he briefly joked that it was Easter and that he was dressed up as "Father Easter". Danny was in reality dead at this point in her timeline. (TV: Last Christmas)