In [U]mbra : ǂb демонология как семиотическая система / ǂc ответственные редакторы и составители Д. И. Антонов, О. В. Христофорова. (OCLC #896742190)

Even on the title page, the U in the word “Umbra” is represented as some kind of animal; it is probably a demon, given the subject of the book.

RDA 1.7.5 on Symbols has an LC-PCC PS with instructions on handling symbols with an obvious spoken or written equivalent, which the picture of the demon has. I added a note about this detail:

500 __ ǂa On title page, "[U]" appears as a demon.