Mari Lwyd

[Acidic Angel]

In the darkest months of the Welsh year, a white horse appears: the mysterious, menacing Mari Lwyd.
Mari Lwyd is a Welsh tradition that takes place on Christmas, roughly translating to "Grey Mare", Mari visits a village with her group.
When the groups get to a house, they sing Welsh language songs or wassails, or more traditionally indulge in a ritual called pwnco: an exchange of rude rhymes with the person who lives there. If the Mari and her gang get entry, the household is said to have good luck for the year. The Mari is well-known to be mischievous – trying to steal things and chase people she likes – as she goes about her bidding.

*I did my best here, it's not a completely accurate representation but it's all I could manage with my items.