Lydia is easily persuaded into being an elf to accompany Santa. It's still better than the bunny costume Delia made her... Christmas/Starlight isn't her passion the way Halloween is, but she's festive anyways in her red spider-web poncho and green-elf-hat. Handing out candy-canes and trying to reassure anyone scared that nope, Santa is really the good guy.

It's Krampus you have to watch out for, after all.