Source: A Caroling Horse (Of Course. Of Course.), pg(s). Paizo Blog
The Mari Lwyd is a fey being that appears during winter holidays, seeking to celebrate and revel.
The Mari Lwyd appears as a tall form cloaked in a white shroud with a horse's skull for a head.
Habitat and ecology
The Mari Lwyd appears during holidays and approaches inhabited structures. When it finds a suitably occupied building, it begins to sing in rhyme, calling out to those within to beseech them for entry and supplicate them for drink and food. Those within must sing back and rebuke it. The two sides sing back and forth until one wins. If the inhabitants of the building win, the Mari Lwyd is turned away and departs. If the Mari Lwyd wins, it enters the structure. Once it passes the threshold, those within the building have a short window of time to demand it behave itself and to offer it either alcohol or cheese. If one or both of these things are not done, the Mari Lwyd begins to carouse with destructive effect. This typically ends in furniture being destroyed, stores of food and drink being emptied, and the building generally wrecked. However, it never harms creatures during this celebration, and turns to violence only if attacked first.
The exact nature of "cheese" has yet to be determined by Golarian scholars, but the general definition for an offering to the Mari Lwyd is that if you have to ask whether it is cheese, it is not.
The Mari Lwyd's song, called a Pwnco, is a powerful magical effect. By beginning it, the Mari Lywd challenges the inhabitants of the building it has approached, and it cannot stop it before the challenge reaches its conclusion. If it wins the challenge, or if no one replies to its most recent verse, the door unlocks and opens, mundane barriers move aside, and magical barriers are dispelled.
To aid it in its wassailing, the Mari Lwyd is immune to most magical effects and all mundane effects that would silence it. It always knows if a building is unoccupied, if it is occupied but the inhabitants cannot hear the Mari Lwyd's song or cannot sing back, or it it is occupied but the inhabitants are ignoring or willfully refusing to answer the challenge. It moves swiftly across land and can swim easily through water, allowing it to quickly travel between potential revels.
The Mari Lywd has an unusual relationship with violence. It is incapable of inflicting true harm on any creature that did not attempt to harm it first. When not given an offering and ordered to behave, attempts to harm it are less effective and it can tear through wood, stone, and iron with ease so long as it does not leave the building; however, it loses these benefits if it attempts to harm any creature.
- ↑ Note that in the chat of the associated Paizo Blog, Aaron Shanks suggests that this creature may not be part of Lost Omens canon.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Eleanor Ferron. (January 1, 2021). A Caroling Horse (Of Course. Of Course.), Paizo Blog.
- Mari Lwyd (Real-life folk custom) on Wikipedia