santa hat
Sometimes yukkuris wears a santa hat around christmas. In some stories they are born wearing a santa hat (though they're never treated as a rare species unlike shell or kotatsu marisas). In other stories a human gives them santa hats to wear (usually to sell them as christmas goods), being one of the rare cases where a yukkuri is willing to wear alternate accessories. Marisa types seems to be the types to wear santa hats the most often, being called santa marisas.
As the main purpose of making them wear santa hats is for humans to sell them as christmas goods, a common story element in stories where yukkuris wear santa hats is the unsold yukkuris being abandoned as trash once christmas day has passed