Donder, I think it was - one of the reindeer - and his wife have given birth to Rudolph, who has a glowing red nose. All of the other reindeer have black noses. The parents are scared that their offspring will not be approved of by Santa for this and make a dark cover to slide over his nose to cover its red glow. When Santa comes to their cave (the reindeer live in caves) to meet Rudolph, the parents are scared Santa will discover the "defect" (my word, not theirs) and disapprove of him.
This scene could be straight out of Roots.
A silly thought, I realize...but then again, maybe it's not.