X is one of those awful letters that drive me spare, and force a shotgunning of stuff onto the blog.
Xenos is my Warhammer 40k gaming side showing. In that context, 'Xenos' is the other, the alien. Which given the nature of humanity in this particular wargame, simply means a "them and us" attitude and more shooting. The human race in the year 40000 is a xenophobic, racist, violent facist galactic empire that in the name of keeping itself safe, will destroy solar systems and commit genocide. That concept, coupled with my pacisim, made for some slightly strange self debate about fictional games.
But, anyway, Gef as some kind of alien is slightly too outlandish for this particular series of outlandish events.
Xenophobia doesn't quite fit.
Xenoglossia (you can tell I hit the dictionary, right?) is a phenomena where mediums claim to be able to speak a language that they're unfamiliar with. Which is another interesting piece of a puzzle from a different box. Perhaps for the story of Harry Price and his frequent run-ins with mediums and spirit talkers.
Xenobiology: the study of alien beings. The word that seems more suited to Gef is cryptozoology which is, very roughly, the study of odd terrestrial creatures.
Could these things be usefully included in the play? At the least the would be simple colour, part of the background. The Xenoglossia is probably the most appropriate idea to slap in there as part of the travelling Harry Price show- some weird citified circus barker offering to puncture the fiction of your friendly neighbourhood spirit medium.